This CL fixes two bugs:
- Play/pause button toggling looked inconsistent when playback fails.
When player state goes into idle, play button should dispatch
playwhenready again.
- Clicking play button at the end of stream should restart playback.
But previously it changed playwhenready state and so playback has
been paused. This CL fix it.
PiperOrigin-RevId: 329675660
