Update 2.9.4 release notes
Update 2.9.4 release notes

PiperOrigin-RevId: 230220448

androidx/media,stari4ek/ExoPlayer,ened/ExoPlayer,saki4510t/ExoPlayer,google/ExoPlayer,saki4510t/ExoPlayer,superbderrick/ExoPlayer,superbderrick/ExoPlayer,saki4510t/ExoPlayer,stari4ek/ExoPlayer,amzn/exoplayer-amazon-port,amzn/exoplayer-amazon-port,amzn/exoplayer-amazon-port,google/ExoPlayer,google/ExoPlayer,ened/ExoPlayer,superbderrick/ExoPlayer,androidx/media,androidx/media,ened/ExoPlayer,stari4ek/ExoPlayer