Remove duplicate release notes
Remove duplicate release notes

These changes are all in 2.12.3, they shouldn't be in the 2.13.0
section.

#minor-release

PiperOrigin-RevId: 353855677

ened/ExoPlayer,google/ExoPlayer,amzn/exoplayer-amazon-port,ened/ExoPlayer,androidx/media,androidx/media,google/ExoPlayer,amzn/exoplayer-amazon-port,androidx/media,amzn/exoplayer-amazon-port,google/ExoPlayer,ened/ExoPlayer