Add link to annual media developer survey.
Add link to annual media developer survey.

This will be removed after the survey has closed in ~1 month.

PiperOrigin-RevId: 399890121

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