Adds the ability for the iOS text selection menu to handle items that are too wide for the screen.

* replace simple Container(w & h) with SizedBox

* address review comments

* address review comments

This updates the Action API in accordance with the design doc for the changes: flutter.dev/go/actions-and-shortcuts-design-revision

Fixes #53276

This reverts commit 7edcc92b.

This converts Diagnosticable to be a mixin instead of an abstract class, so that it can be used to add diagnostics to classes which already have a base class.

It leaves in place the DiagnosticableMixin mixin, since there are some plugins that are still using it, and removing it would mean that those plugins wouldn't work with master branch Flutter anymore. DiagnosticableMixin will be removed once this mixin version of Diagnosticable makes its way to the stable branch.

This PR adds the linux and windows target platform enum values, along with automatically setting the defaultTargetPlatform to the appropriate value on those platforms.

Fixes #31366

This reverts commit 2132a0c7.

This reverts commit 69080e07.

This PR is a follow up of https://github.com/flutter/flutter/pull/42640
Some changes of that PR includes redundant changes using FlutterError.fromParts constructor even though it's not necessary.

Some minor changes are:

- Remove one unnecessary todo
- Fix indent consistencies

* reland "Refactors global key duplication detection (#46183)"

This reverts commit d2b66dbf.

* fix test

This reverts commit 340b193f.

This PR fixes #49647 by changing DiagnosticableMixin.toDiagnosticsNode and other things to accept DiagnosticableMixin instead of requiring Diagnosticable.

Navigator 2.0: Refactor the imperative api to continue working in the new navigation system (#44930)

[a11y] Make sure RenderFractionalTranslation updates its semantics after the translation field is set (#48985)