1286 [in_app_purchase] Adds Dart BillingClient APIs for loading purchases (cla: yes)

1288 [image_picker] delete original file if scaled (cla: yes)

1289 Add missing license headers (cla: yes)

1291 Bugfix/account for nsnull (cla: yes)

1292 [firebase_auth] Make providerId ‘const String’ for easier use in switch statements (bugfix, cla: yes, flutterfire, submit queue)

1293 [google_maps_flutter] The FloatingActionButton requires an icon (cla: yes)

1294 Fix icon issue on ios and manifest on android (cla: yes)

1296 [image_picker] Update pub info for #742 (cla: yes)