Closes #132245.

Partial work towards https://github.com/flutter/flutter/issues/132245.

The goal here is to "sniff" out any missing pieces that would block engine builds, rolls, benchmarks and so on before requiring humans to provide the parameter. The implementation is based on a [short discussion with @christopherfujino](https://discord.com/channels/608014603317936148/608022056616853515/1141503921546875110):

@matanlurey:

> Not sure whether to post here or ⁠hackers-infra-🌡 , but is there a way to (and is it advisable to) detect whether the tool is running in a CI environment? I'd like to "soft enforce" --local-engine-host being provided strictly on CI, make sure that lands well, and then "upgrade" it to being non-CI invocations as well (re: https://github.com/flutter/flutter/issues/132245).
>
> Also happy to get talked out of this idea 🙂

@christopherfujino:

> we have a check, lemme find it
> whether or not it is advisable, idk
> https://github.com/flutter/flutter/blob/flutter-3.14-candidate.0/packages/flutter_tools/lib/src/base/bot_detector.dart#L30
>
> (...)
>
> is your desire to get early signal before enforcing t his for humans to prevent functionality churn of landing and reverting and re-landing? 
>
> (yes)
>
> uhh, sure, that's advisable 🙂

Closes https://github.com/flutter/flutter/issues/132162.

I did a tiny bit of minor cleanup but didn't want to go  beyond the
scope of this change. After it lands I'll update the Wiki.

## Before

```bash
$ fl run \
  --local-engine-src-path=$ENGINE \
  --local-engine=android_debug_unopt_arm64
```

... would try to use `host_debug_unopt` (i.e. Rosetta).

## After

```bash
$ fl run \
  --local-engine-src-path=$ENGINE \
  --local-engine=android_debug_unopt_arm64 \
  --local-engine-host=host_debug_unopt_arm64
```

... uses `host_debug_unopt_arm64`, as specified.

---

/cc @jonahwilliams @gaaclarke @zanderso

<img width="919" alt="image" src="https://github.com/flutter/flutter/assets/42003129/4bc8c3b8-29af-4b98-9232-47a583523e3c">
I was installing Flutter and noticed that the download link for Xcode is incorrect. They might have changed it, but the current link doesn't exist.

I intend to edit `toBeginningOfSentenceCase`'s return value to be non-nullable because it really is never null. That will mean that non-null asserts around it will become flagged as unnecessary, although right now they are necessary. So, apply a workaround - instead use a function that does a non-null assert without triggering any lints even after it becomes unnecessary.

Presubmit testing and CI testing of Flutter using a custom storage location for engine artifacts must be able to use the --fatal-warnings flag without failing due to the custom artifact location.

This change adds an option that makes this warning non-fatal. The new --no-fatal-storage-url-warning flag makes the --fatal-warnings flag ignore the warning that a custom artifact download URL is being used by setting the environment variable FLUTTER_STORAGE_BASE_URL.

Bug: #127683

- [X ] I read the [Contributor Guide] and followed the process outlined there for submitting PRs.
- [X ] I read the [Tree Hygiene] wiki page, which explains my responsibilities.
- [X ] I read and followed the [Flutter Style Guide], including [Features we expect every widget to implement].
- [X ] I signed the [CLA].
- [X ] I listed at least one issue that this PR fixes in the description above.
- [X ] I updated/added relevant documentation (doc comments with `///`).

This reverts commit 2b3cd7f4.

Fixes https://github.com/flutter/flutter/issues/127281.

Give channel descriptions in `flutter channel`, use branch instead of upstream for channel name (#126936)

## How we determine the channel name

Historically, we used the current branch's upstream to figure out the current channel name. I have no idea why. I traced it back to https://github.com/flutter/flutter/pull/446/files where @abarth implement this and I reviewed that PR and left no comment on it at the time.

I think this is confusing. You can be on a branch and it tells you that your channel is different. That seems weird.

This PR changes the logic to uses the current branch as the channel name.

## How we display channels

The main reason this PR exists is to add channel descriptions to the `flutter channel` list:

```
ianh@burmese:~/dev/flutter/packages/flutter_tools$ flutter channel
Flutter channels:
  master (tip of tree, for contributors)
  main (tip of tree, follows master channel)
  beta (updated monthly, recommended for experienced users)
  stable (updated quarterly, for new users and for production app releases)
* foo_bar

Currently not on an official channel.
ianh@burmese:~/dev/flutter/packages/flutter_tools$
```

## Other changes

I made a few other changes while I was at it:

* If you're not on an official channel, we used to imply `--show-all`, but now we don't, we just show the official channels plus yours. This avoids flooding the screen in the case the user is on a weird channel and just wants to know what channel they're on.
* I made the tool more consistent about how it handles unofficial branches. Now it's always `[user branch]`.
* I slightly adjusted how unknown versions are rendered so it's clearer the version is unknown rather than just having the word "Unknown" floating in the output without context.
* Simplified some of the code.
* Made some of the tests more strict (checking all output rather than just some aspects of it).
* Changed the MockFlutterVersion to implement the FlutterVersion API more strictly.
* I made sure we escape the output to `.metadata` to avoid potential injection bugs (previously we just inlined the version and channel name verbatim with no escaping, which is super sketchy).
* Tweaked the help text for the `downgrade` command to be clearer.
* Removed some misleading text in some error messages.
* Made the `.metadata` generator consistent with the template file.
* Removed some obsolete code to do with the `dev` branch.

## Reviewer notes

I'm worried that there are implications to some of these changes that I am not aware of, so please don't assume I know what I'm doing when reviewing this code. :-)

Fixes the `findBundleFile` method in `gradle.dart` to correctly locate app bundles generated from multiple flavor dimensions.

- closes https://github.com/flutter/flutter/issues/92316
- closes https://github.com/flutter/flutter/issues/65264

Instead of using rsync, which has caused errors in the past (https://github.com/flutter/flutter/issues/99785), delete the file/directory/link prior to moving it.

Hopefully should let us stop double zipping the FlutterMacOS.framework in the engine: https://github.com/flutter/engine/pull/41306/files

Part of https://github.com/flutter/flutter/issues/126016.

Update `flutter doctor` to clarify that Visual Studio is needed only if creating Windows apps. Windows users targeting Android do not need to install Visual Studio.

Adds `todo` link in code for #125155.

Rename variables, update comments, etc from `network` to `wireless` to keep it more uniform.

Also, move non-overriden messages related to device selection into the file they're used.

Part 7 in breakdown of https://github.com/flutter/flutter/pull/121262.

Fixes #124756 by removing the concept of `Version.unknown`.

`Version` fields that needed the ability to represent an unknown version have been made nullable. Assigning `null` to them represents an unknown version.

flutter-tool: enum cleanup

https://github.com/flutter/flutter/issues/123917

Doc covering a broad set of issues related to android studio updating. 

https://docs.google.com/document/d/1hTXkjbUrBnXgu8NQsth1c3aEqo77rWoEj8CcsQ39wwQ/edit?pli=1#

Specifically this pr: 
- Adds new functions to find a projects AGP, Gradle and java versions,
and tests.
- Adds new functions that take versions and parse if the versions are
compatible with each other, and tests.
- Adds validator for `flutter analyze --suggestions` that evaluates the
java/gradle/agp versions and checks if they are compatible, and
integration test.
- Updates the version of gradle used by
dev/integration_tests/flutter_gallery/ to the minimum supported by java
18 so that the integration tests pass (It is unknown why the java
version is 18.9 instead of 11)
- Moves `isWithinVersionRange` to version.dart, and tests. 
- Adds FakeAndroidStudio to fakes to be used in multiple tests but does
not remove existing copies.

Metrics will be included as part of the definition of done for this bug
but not as part of this cl. It is already too big.

Known work still left in this pr: 
* Understand why analyze integration tests are failing. 


Example output if Java and gradle are not compatible: 
```
┌───────────────────────────────────────────────────────────────────┐
│ General Info                                                      │
│ [✓] App Name: espresso_example                                    │
│ [✓] Supported Platforms: android                                  │
│ [✓] Is Flutter Package: yes                                       │
│ [✓] Uses Material Design: yes                                     │
│ [✓] Is Plugin: no                                                 │
│ [✗] Java/Gradle/Android Gradle Plugin:                            │
│                                                                   │
│ Incompatible Java/Gradle versions.                                │
│                                                                   │
│ Java Version: 17.0.6, Gradle Version: 7.0.2                       │
│                                                                   │
│ See the link below for more information.                          │
│ https://docs.gradle.org/current/userguide/compatibility.html#java │
│                                                                   │
└───────────────────────────────────────────────────────────────────┘
```
Example output if Gradle and AGP are not compatible
```
┌─────────────────────────────────────────────────────────────────────────────┐
│ General Info                                                                │
│ [✓] App Name: espresso_example                                              │
│ [✓] Supported Platforms: android                                            │
│ [✓] Is Flutter Package: yes                                                 │
│ [✓] Uses Material Design: yes                                               │
│ [✓] Is Plugin: no                                                           │
│ [✗] Java/Gradle/Android Gradle Plugin: Incompatible Gradle/AGP versions.    │
│                                                                             │
│ Gradle Version: 7.0.2, AGP Version: 7.4.2                                   │
│                                                                             │
│ Update gradle to at least "7.5".                                            │
│ See the link below for more information:                                    │
│ https://developer.android.com/studio/releases/gradle-plugin#updating-gradle │
│                                                                             │
│ Incompatible Java/Gradle versions.                                          │
│                                                                             │
│ Java Version: 17.0.6, Gradle Version: 7.0.2                                 │
│                                                                             │
│ See the link below for more information:                                    │
│ https://docs.gradle.org/current/userguide/compatibility.html#java           │
│                                                                             │
└─────────────────────────────────────────────────────────────────────────────┘
```
Example output if Java/Gradle/Agp are not compatible. 
```

┌─────────────────────────────────────────────────────────────────────────────┐
│ General Info                                                                │
│ [✓] App Name: espresso_example                                              │
│ [✓] Supported Platforms: android                                            │
│ [✓] Is Flutter Package: yes                                                 │
│ [✓] Uses Material Design: yes                                               │
│ [✓] Is Plugin: no                                                           │
│ [✗] Java/Gradle/Android Gradle Plugin: Incompatible Gradle/AGP versions.    │
│                                                                             │
│ Gradle Version: 7.0.2, AGP Version: 7.4.2                                   │
│                                                                             │
│ Update gradle to at least "7.5".                                            │
│ See the link below for more information:                                    │
│ https://developer.android.com/studio/releases/gradle-plugin#updating-gradle │
│                                                                             │
│ Incompatible Java/Gradle versions.                                          │
│                                                                             │
│ Java Version: 17.0.6, Gradle Version: 7.0.2                                 │
│                                                                             │
│ See the link below for more information:                                    │
│ https://docs.gradle.org/current/userguide/compatibility.html#java           │
│                                                                             │
└─────────────────────────────────────────────────────────────────────────────┘
```

Commit messages
- Add function to gradle_utils.dart that gets the gradle version from
wrapper or system and add a test for each situation
- Add method to get agp version, add method to validate agp against
gradle version, update documentation, add tests for agp validation.
- Update dart doc for validateGradleAndAgp to describe where the info
came from and corner case behavior, create function to validate java and
gradle and hardcode return to false
- Fill out and test java gradle compatibility function in gradle_utils
- Hook up java gradle evaluateion to hasValidJavaGradleAgpVersions with
hardcoded java version
- Add java --version output parsing and tests
- Add getJavaBinary test
- Update comment in android_sdk for mac behavior with java_home -v

## Pre-launch Checklist

- [x] I read the [Contributor Guide] and followed the process outlined
there for submitting PRs.
- [x] I read the [Tree Hygiene] wiki page, which explains my
responsibilities.
- [x] I read and followed the [Flutter Style Guide], including [Features
we expect every widget to implement].
- [x] I signed the [CLA].
- [x] I listed at least one issue that this PR fixes in the description
above.
- [x] I updated/added relevant documentation (doc comments with `///`).
- [x] I added new tests to check the change I am making, or this PR is
[test-exempt].
- [ ] All existing and new tests are passing.

Update device selection to wait for wireless devices to load

Add flags to make App.framework work in app extension

[Focus] Add run key command to dump the focus tree

Remove 1745 decorative breaks

Enable prefer_mixin

Separate attached and wireless devices

This reverts commit 275ab9c6.

Revert "Reland "Remove references to Observatory (#118577)""

This reverts commit 298d8c76.

* Fix typos

* lowercase animated & opacity

* Undo typo fix

---------
Co-authored-by: Michael Goderbauer <goderbauer@google.com>

* lerp documentation

* Remove Note, Note That from repo

* Improve BorderSide documentation.

* apply review comments

This reverts commit 2df140f4.

...and various other minor cleanup:

* Moved "FLUTTER_STORAGE_BASE_URL" into a constant throughout the code. There are other strings that we should do that to but this one was relevant to the code I was changing.

* Fixed the logger's handling of slow warnings. Previously it deleted too much text. Fixed the test for that to actually verify it entirely, too.

* Made the logger delete the slow warning when it's finished.

* Fixed 'Please choose one (To quit, press "q/Q")' message to be the cleaner 'Please choose one (or "q" to quit)'.

* Added a debug toString to ValidationResult for debugging purposes (not used).

* In http_host_validator:

  - Shortened constant names to be clearer (e.g. kPubDevHttpHost -> kPubDev).
  - Added GitHub as a tested host since when you run `flutter` we hit that immediately.
  - Renamed the check "Network resources".
  - Updated the `slowWarning` of the check to say which hosts are pending.
  - Removed all timeout logic. Timeouts violate our style guide.
  - Removed `int.parse(... ?? '10')`; passing a constant to `int.parse` is inefficient.
  - Replaced the `_HostValidationResult` class with `String?` for simplicity.
  - Improved the error messages to be more detailed.
  - Removed all checks that dependened on the stringification of exceptions. That's very brittle.
  - Added a warning specifically for HandshakeException that talks about the implications (MITM attacks).
  - Replaced exception-message-parsing logic with just calling `Uri.tryParse` and validating the result.
  - Replaced a lot of list-filtering logic with just a single for loop to check the results.
  - Replaced code that added a constant to a known-empty list with just returning a constant list.
  - Revamped the logic for deciding which hosts to check to just use a single chain of if/else blocks instead of getters, lists literals with `if` expressions, `??`, functions, etc spread over multiple places in the code.

Observatory is being deprecated for Dart 3.0 so it should no longer be
referenced in tooling messaging / flags.

See https://github.com/dart-lang/sdk/issues/50233

* feat: add "--resolve-dwarf-paths" to gen_snapshot

* chore: update tests

This reverts commit 254a796b.

* fix

* add test