1485 Fix unused vars and rename (cla: yes)

1486 [firebase_performance] Firebase Performance integration tests (cla: yes)

1487 [firebase_auth] Migrate FlutterAuthPlugin from deprecated APIs (cla: yes, flutterfire)

1488 [image_picker]version fix. (cla: yes)

1489 BitmapDescriptor#fromBytes should be consistent across platforms (cla: yes)

1490 [firebase_analytics] Fixes errors in firebase_analytics docs (cla: yes)

1491 [cloud_firestore] Support for atomic FieldValue.increment (cla: yes, feature, flutterfire)

1492 [firebase_analytics] Initial integration test (cla: yes, flutterfire)