3604 [connectivity_macos] fix flutter version constraint (cla: yes, p: connectivity, platform-macos)

3644 [path_provider] Migrate all integration tests to NNBD (cla: yes, p: path_provider, platform-linux, platform-macos, platform-windows)

3661 Remove unused plugin (integration_test_macos) (cla: yes, p: integration_test, platform-macos, waiting for tree to go green)

3681 [ci] Disable analyze on stable for web plugins that contains null safety integration tests.  (cla: yes, p: connectivity, p: google_sign_in, p: image_picker, platform-macos)