Remove broadcastMetadata trigger.

On some devices the play/pause status would go through an extra
transition due to the value provided by the Media Browse Service not
being in line with the actual state.  By eliminating that state we
eliminate the race condition.

Bug: 74605206
Test: runtest bluetooth -p com.android.bluetooth.a2dpsink
Change-Id: I0b7716f1d1602e81ff050ca2b268ae036265b1c6
(cherry picked from commit 6d756e22abf77db19c0cb45877b78f61b9e801af)