29427 Cherry pick a revert on flutter-2.8-candidate.2 to unblock the internal roll. (cla: yes, needs tests)

platform-fuchsia - 81 pull request(s)

26880 Migrated integration_flutter_test/embedder (scenic integration test) from fuchsia.git (cla: yes, waiting for tree to go green, platform-fuchsia, needs tests)

26996 Add SPIR-V FragmentShader API to painting.dart (platform-android, cla: yes, platform-web, platform-fuchsia)

27423 fuchsia: Add scaffolding and basic implementation for flatland migration (cla: yes, platform-fuchsia)

27849 [fuchsia] [ffi] Basic support for Channels and Handles (cla: yes, waiting for tree to go green, platform-fuchsia)