4341 [flutter_plugin_tools] Make no unit tests fatal for iOS/macOS (cla: yes, p: share, p: quick_actions, platform-ios)

4342 [camera_web] Release the camera stream used to request video and audio permissions (cla: yes, waiting for tree to go green, p: camera, platform-web)

4343 [webview_flutter] Extract Android implementation into a separate package (cla: yes, p: webview_flutter, platform-android)

4344 [video_player] Fix a disposed VideoPlayerController throwing an exception when being replaced in the VideoPlayer (cla: yes, p: video_player)

4345 [webview_flutter] Extract WKWebView implementation into a separate package (cla: yes, p: webview_flutter, platform-ios)