SDK / exoplayer

- Remove manifest argument from callbacks of Player.EventListener and
  SourceInfoRefreshListener. Instead make it accessible through
  Player.getCurrentManifest() and Timeline.Window.manifest.
- Fix all MediaSource implementation to include the manifest in the
  Timeline instead of passing it to the SourceInfoRefreshListener.
- Refactor ExoPlayerTestRunner, FakeTimeline, FakeMediaSource to
  reflect these changes and make tests pass.

PiperOrigin-RevId: 257359662