Merge "Replace PlaybackActivityMonitor with AudioDeviceCallback" am: 3424cdb269

Original change: https://android-review.googlesource.com/c/platform/packages/apps/MusicFX/+/2504276

Change-Id: I3906cd8dbc780f88a29b61043b29e521ca142148
Signed-off-by: Automerger Merge Worker <[email protected]>