2261 [image_picker] more documentations and tests. (cla: yes)

2262 [connectivity] add more documentations, delete example/README (cla: yes)

2266 [google_sign_in] Port plugin to use the federated Platform Interface (cla: yes)

2267 Bump google_maps_flutter pubspec version to match CHANGELOG (cla: yes)

2268 [android_intent] Add missing DartDocs (cla: yes)

2269 [connectivity] Lint for public DartDocs (cla: yes)

2270 [image_picker] Lint for public DartDocs (cla: yes)

2271 [infra] Ignore analyzer issues in CI (cla: yes)

2272 [sensors] Documentation and test improvements (cla: yes)