Fixed types for `_getNewServiceWorker` and `_waitForServiceWorkerActivation` functions.  
These functions currently expect a Promise as an argument, but we're actually passing in an already resolved value:
```js
.then(this._getNewServiceWorker)
.then(this._waitForServiceWorkerActivation);
```

- `ui_web.warmupEngine`
- `ui_web.setPluginHandler`
- `ui_web.debugEmulateFlutterTesterEnvironment`

Flutter web uses requireJS in `debug` mode to assemble a DDC-compiled app from a bunch of small files ("modules").

This caused that `canvaskit.js` (and all other modules that used a browserify-like loading header) didn't work because they attempted to use the `define` function provided by Flutter's instance of `requireJS` (which kept the defined modules private, rather than as globals on the page, as the users of the JS expected).

A [fix](https://github.com/flutter/engine/pull/27342) was added to `flutter/engine` to trick loaders into *not* using the `requireJS` module loader, but a recent change in the fix's js-interop layer *subtly* changed its JS output on the page (objects went from `undefined` to `null`), causing this:

* https://github.com/flutter/flutter/issues/126131 (and others)

This PR hides a bit of code that is commonly used by module loaders to decide that they may use the `define` function provided by requireJS (so the engine workaround can be removed).

## Next steps

* https://github.com/flutter/engine/pull/42941

## Issues

Partially addresses: https://github.com/flutter/flutter/issues/126131 (and others)

## Tests

* Added a unit test to ensure the `delete` stays
* Manually tested with the Gallery app in `debug` mode with a bunch of user-supplied scripts that currently fail to load.
  * Also tested hot restart as suggested by @nshahan

Replace imports of `src/remote_listener.dart` with `backend.dart` which exports `RemoteListener`.

Remove the unused imports of `src/backend/stack_trace_formatter.dart` (no uses of `StackTraceFormatter`) and
`src/backend/suite_channel_manager.dart` (no uses of `SuiteChannelManager`).

Filtering on 'true' omitted non-bool values

Missing "tick"

Allows controlling a broader set of variables than just on/off.

Also make wasm-opt "full" the default

Also fixed some comments

Addresses part of https://github.com/flutter/flutter/issues/125164

Fixes https://github.com/flutter/flutter/issues/125085

This fixes https://github.com/flutter/flutter/issues/124159

Adds the command line argument `--wasm-opt` to optimize the web assembly output.

flutter-tool: enum cleanup

flutter_tools: Flutter Web CLI cleanup

Add omit-type-checks flag for wasm builds

Add support to the flutter tool to compile against the skwasm renderer

flutter tool: log dart2wasm vs dart2js as appropriate during build

Revert "flutter tool: log dart2wasm vs dart2js as appropriate during build"

flutter tool: log dart2wasm vs dart2js as appropriate during build

flutter_tool: add and use WebCompilerConfig

Add tools test for buildWeb compilation

Revert "[flutter_tools] Remove sound null safety flag (#123031)"

[flutter_tools] Remove sound null safety flag #2

This reverts commit 7c3088cf.

[flutter_tools] Remove sound null safety flag

Revert "[web:tools] always use CanvasKit from the cache when building web apps (#93002)"

[flutter_tool] advertise the default value for --dart2js-optimization

This reverts commit 275ab9c6.

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

Revert "[flutter_tools] show web-server in flutter devices"

This reverts commit 298d8c76.

[flutter_tools] show web-server in flutter devices

* Fix typos

* lowercase animated & opacity

* Undo typo fix

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

* Allow any JS file in flutter loader.

* Nag only if service worker API is completely unavailable.

* Add info about Secure Contexts if that may be the reason why serviceworker is not available.

* Update sanity test.

* If service worker settings are null, do not even check if the API is available.

* lerp documentation

* Remove Note, Note That from repo

* Improve BorderSide documentation.

* apply review comments

This reverts commit 2df140f4.

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

This reverts commit 0fb4406c.