[Output Switcher] Improvement for seekbar volume control

1. dispatchDataChanged will not build devices again, we need to
   do that to update volume quicker.
2. dismiss dialog only when Media change to pause or stop.

Bug: 243759774
Test: verified on device
Change-Id: I9b93c7e21c899f011418ee51cec3be08c30004fa
3 files changed