AudioService: stop SCO audio when communication route client dies

Fix AudioDeviceBroker.onCommunicationRouteClientDied() implementation
to actually stop BT SCO audio in case of client death.
Previous implementation was just removing the client from the client
list and restoring audio route but wihtout stopping the actual SCO audio
link.

Bug: 196922082
Test: repro steps in bug
Change-Id: I381537f61740f9a9fcbf3232ef4336943b0826c5