Change the following in the `flutter create` templates.  I didn't make any auto-migrations for existing apps because none seem that critical:
1. Turn on `ASSETCATALOG_COMPILER_GENERATE_SWIFT_ASSET_SYMBOL_EXTENSIONS` in iOS and macOS.
1. Turn on `BuildIndependentTargetsInParallel` in macOS template.  https://github.com/flutter/flutter/pull/125827/files#r1181817619 
1. Turn on `DEAD_CODE_STRIPPING` in macOS template. 
1. Set `ENABLE_USER_SCRIPT_SANDBOXING=NO` in iOS and macOS template.  `flutter` scripts don't work with this on.  This might require a migration in the future to explicitly turn this one off. However at least for now if the setting isn't present it defaults to `NO`.

Add migration for `LastUpgradeVersion` so users won't see these validation issues in Xcode.

Run migrator on all the example apps.  A few aren't Flutter apps so I edited them in Xcode.

Fixes https://github.com/flutter/flutter/issues/140253
See also https://github.com/flutter/flutter/issues/125817 and https://github.com/flutter/flutter/pull/90304.

Reland https://github.com/flutter/flutter/pull/140478 with `ios_content_validation_test` test fix.
```
[ios_content_validation_test] Process terminated with exit code 0.
Task result:
{
  "success": true,
  "data": null,
  "detailFiles": [],
  "benchmarkScoreKeys": [],
  "reason": "success"
}

```

__________

1. Change templates to `IPHONEOS_DEPLOYMENT_TARGET`, `MinimumOSVersion`, and Podfile `platform :ios` to 12.0.
2. Add migrator for Podfile part to migrate `platform :ios, '11.0'` -> `platform :ios, '12.0'`
3. Compile with `-miphoneos-version-min=12.0`
4. Run the migrator on all example apps and integration tests.

See also https://github.com/flutter/flutter/pull/62902 and https://github.com/flutter/flutter/pull/85174 and https://github.com/flutter/flutter/pull/101963

Fixes https://github.com/flutter/flutter/issues/136060

Reverts flutter/flutter#140478
Initiated by: loic-sharma
This change reverts the following previous change:
Original Description:
1. Change templates to `IPHONEOS_DEPLOYMENT_TARGET`, `MinimumOSVersion`, and Podfile `platform :ios` to 12.0.
2. Add migrator for Podfile part to migrate `platform :ios, '11.0'` -> `platform :ios, '12.0'`
3. Compile with `-miphoneos-version-min=12.0`
4. Run the migrator on all example apps and integration tests.

See also https://github.com/flutter/flutter/pull/62902 and https://github.com/flutter/flutter/pull/85174 and https://github.com/flutter/flutter/pull/101963

Fixes https://github.com/flutter/flutter/issues/136060

1. Change templates to `IPHONEOS_DEPLOYMENT_TARGET`, `MinimumOSVersion`, and Podfile `platform :ios` to 12.0.
2. Add migrator for Podfile part to migrate `platform :ios, '11.0'` -> `platform :ios, '12.0'`
3. Compile with `-miphoneos-version-min=12.0`
4. Run the migrator on all example apps and integration tests.

See also https://github.com/flutter/flutter/pull/62902 and https://github.com/flutter/flutter/pull/85174 and https://github.com/flutter/flutter/pull/101963

Fixes https://github.com/flutter/flutter/issues/136060

Some files are supposed to ignore, but don't.

- **/windows/flutter/generated_plugins.cmake
- **/linux/flutter/generated_plugin_registrant.cc
- **/linux/flutter/generated_plugin_registrant.h
- **/linux/flutter/generated_plugins.cmake
- **/windows/flutter/generated_plugin_registrant.cc
- **/windows/flutter/generated_plugin_registrant.h
- **/ios/Runner/GeneratedPluginRegistrant.h
- **/ios/Runner/GeneratedPluginRegistrant.m

*List which issues are fixed by this PR. You must list at least one issue.*

*If you had to change anything in the [flutter/tests] repo, include a link to the migration guide as per the [breaking change policy].*

Now that we support UIViewControllerBasedStatusBar by default (after engine roll: https://github.com/flutter/flutter/commit/c7167765d74c1980c9ba750c5750ae27817ad630), we should make this value to be true.

Part of https://github.com/flutter/flutter/issues/128969

1. Add iOS and macOS migration to mark "last upgraded" Xcode version to 14.3 to prevent `Update to recommended settings` warning.
2. Update iOS and macOS templates to same.
3. Update iOS template to set `BuildIndependentTargetsInParallel` to YES as suggested.  I didn't add a migration for this since it seems like a minor optimization and I don't think it's worth a potentially botched/corrupted migration.
4. Run all example/integration test project to see migrator work.
5. Add some missing test projects to the build shard since I noticed they were missing and I had to build those manually outside `SHARD=build_tests`.

Fixes https://github.com/flutter/flutter/issues/125817
See https://github.com/flutter/flutter/pull/90304 for Xcode 13 example.

* Add Info.plist from build directory as input path to Thin Binary build phase

* fix directive ordering

* migrate benchmark, integration, and example tests

This reverts commit 6a3ea7eb.

* Revert "Enable dart_plugin_registry_test (#76645)"

This reverts commit 109e0bb9.

* Revert "Apply changes caused by https://github.com/flutter/flutter/pull/76662 (#77093)"

This reverts commit cdca6485.

* Revert "Disable clang format in the plugin registrants (#76662)"

This reverts commit dadbd47d.

* Revert "Disable warnings for the dart plugin registrant (#76561)"

This reverts commit 098ece52.

* Revert "Remove dart_plugin_registry_test timeouts (#76838)"

This reverts commit 1610a274.

* Revert "Implement dartPluginClass support for plugins (#74469)"

This reverts commit b7d48062.

Kick.

This reverts commit 28db5a0f.

* App.framework must support iOS 8 for older Flutter projects

* Fix test

This reverts commit dd9323bd.

This reverts commit 43e28084.

This reverts commit 2054f37a.

* Move embedding and linking Flutter frameworks into the tool

* Unused import

* Migrate

* Rename run, add comments, remove typedef

* Add status log to tell the user what we did

* Remove Podfile migration, create IOSMigration superclass

* word-smiting
Co-Authored-By: Jonah Williams <jonahwilliams@google.com>

* for space
Co-Authored-By: Jonah Williams <jonahwilliams@google.com>
Co-authored-by: Jonah Williams <jonahwilliams@google.com>

* Update project.pbxproj files to say Flutter rather than Chromium

Also, the templates now have an empty organization so that we don't cause people to give their apps a Flutter copyright.

* Update the copyright notice checker to require a standard notice on all files

* Update copyrights on Dart files. (This was a mechanical commit.)

* Fix weird license headers on Dart files that deviate from our conventions; relicense Shrine.

Some were already marked "The Flutter Authors", not clear why. Their
dates have been normalized. Some were missing the blank line after the
license. Some were randomly different in trivial ways for no apparent
reason (e.g. missing the trailing period).

* Clean up the copyrights in non-Dart files. (Manual edits.)

Also, make sure templates don't have copyrights.

* Fix some more ORGANIZATIONNAMEs