Bump Robolectric to 4.6.1
Bump Robolectric to 4.6.1

The bug fix seems potentially serious and worth having:
https://github.com/robolectric/robolectric/releases/tag/robolectric-4.6.1

PiperOrigin-RevId: 383096745

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