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

4356 [quick_actions] Bump minimum Flutter version and iOS deployment target (cla: yes, waiting for tree to go green, p: quick_actions, platform-ios)

4367 Require authors file (cla: yes, p: camera, p: in_app_purchase, p: quick_actions, platform-ios, platform-android, platform-web)

4406 Fix order-dependant platform interface tests (cla: yes, waiting for tree to go green, p: file_selector, p: google_maps_flutter, p: google_sign_in, p: url_launcher, p: video_player, p: quick_actions)