SDK / exoplayer

- Corrected trackEventBytes traversal in TrackChunk where the array position marker was not incremented properly, leading to duplicate sample output.
- Amended TrackEvent "Meta Event" parsing to account for the length of variable length bytes.
- Fixed a bug with TrackEvent message parsing where message data was parsed incorrectly due to miscalculated length.

PiperOrigin-RevId: 456967968