Revert "MediaSession2 API set for audio focus handling"

This reverts commit 5fdfa21144177e8029a734bbe27e170b38a11e15.

Reason for revert: Build break:

https://android-build.googleplex.com/builds/submitted/4568703/taimen-user/latest/logs/build_error.log

Change-Id: I1bc657c3e6e8f65d7362657544f0eb87785dabd7
1 file changed