AVRCP Controller manage focus while disconnected

If Audio focus is lost(or gained)  while A2DP is not connected there is the
possibility for states to get out of sync.  Removing the check for
connectivity ensures that the state can be properly managed.

Bug: 144082798
Test: Disconnect BT device, lose audio focus, verify
btif_a2dp_sink_set_focus_state_event state gets updated.

Change-Id: If5802418f6069dbc72824745307342776175d9d8