Sound + Output Switcher on Sound Setting

1. Show "play media to" item when Previously Connected device is available
2. Click "Play media to" to launch output slice
3. Update test case

Bug: 126475101
Test: make -j50 RunSettingsRoboTests
Change-Id: Id8afd1a2407acb78c11e81d2420ae8c16130a321
8 files changed