4194 [flutter_plugin_tools] Test and comment Dart analysis (cla: yes)

4195 Skip a flaky webview_flutter integration test and extend firebase testlab timeout (cla: yes, p: webview_flutter)

4196 [camera_web] Add takePicture implementation (cla: yes, waiting for tree to go green, p: camera, platform-web)

4197 [camera] Fix camera preview not always rebuilding on orientation change (cla: yes, waiting for tree to go green, p: camera)