4108 Add Basic Junit Tests to some plugins (cla: yes, p: webview_flutter, p: google_sign_in, p: local_auth, p: video_player, p: shared_preferences, platform-android)

4128 Exclude arm64 simulators from google_sign_in example project (cla: yes, p: google_sign_in, platform-ios)

4157 [google_sign_in] Add iOS unit tests (cla: yes, p: google_sign_in, platform-ios)