3985 [video_player_web] fix: set autoplay to false during initialization (cla: yes, waiting for tree to go green, p: video_player, platform-web)

3986 [video_player] Add iOS unit and UI tests (cla: yes, waiting for tree to go green, p: video_player, platform-ios)

4029 [video_player] Remove pre-stable warning from README (cla: yes, p: video_player)