SDK / exoplayer

We recently added code that prevents getting stuck if the buffer is low and
the LoadControl refuses to continue loading (https://github.com/google/ExoPlayer/commit/b84bde025258e7307c52eaf6bbe58157d788aa06).

Move this logic into DefaultLoadControl to keep the workaround, and also apply the
maximum buffer size check in bytes if enabled. ExoPlayerImplInternal will now
throw if a LoadControl lets playback get stuck. This includes the case where
DefaultLoadControl reaches its maximum buffer size and not even a mimimal buffer
duration.

PiperOrigin-RevId: 285979989