[quick_actions] Publish federated version (flutter#5005)

[file_selector] Endorse macOS (flutter#5001)

[file_selector] Add macOS support (flutter#4381)

Brings file_selector_macos into flutter/plugins from FDE, with the following changes:
- Refactored slightly to allow for unit tests of almost all of the native code
- Added native unit test coverage
- Translated to Swift, to follow repo conventions for macOS plugins
- Added an in-package example (almost an exact duplicate of the app-facing version, but written against the platform interface, as is our current practice)
- Moved to an in-package method channel. As part of that, moved the flattening of type groups from Swift to Dart.

Does not currently include native UI tests to allow for end-to-end testing (since Flutter integration tests can't be used). They should be added later (they are currently blocked on flutter/flutter#90673), but the unit tests give substantial coverage, making it substantially better to move the plugin now to get those tests running.

macOS portion of flutter/flutter#70221

[in_app_purchase] Update app-facing package to new analysis options (f…

…lutter#4969)

[google_maps_flutter] Switch app-facing package to new analysis optio…

…ns (flutter#4716)

[in_app_purchase] Update Android to new analysis options (flutter#4937)

[url_launcher] Fixed missing # in links href when opening in new tab …

…on the web (flutter#4221)

[image_picker] Support reading WebP images for iOS (flutter#4448)

[webview] Fix comments (accidentially mixed `//` with `///`) (flutter…

…#4907)

[video_player] Update app-facing package analysis options (flutter#4786)