3506 Run activate before run (cla: yes)

3507 [video_player] Update video_player_platform_interface to latest pigeon (cla: yes, p: video_player)

3509 [file_selector_platform_interface] File selector nnbd (cla: yes, nnbd, p: file_selector, platform-web)

3511 Add a note about Plus plugins to CONTRIBUTING.md (cla: yes)

3512 [google_maps_flutter] fix version (cla: yes, p: google_maps_flutter, waiting for tree to go green)

3513 Update to ffi 0.3.0-nullsafety.1 (cla: yes, p: path_provider, platform-windows)

3515 Remove stray dependency (cla: yes, p: shared_preferences, platform-windows)