[Sound Panel] Fix bugs for sound panel slice

1. notify item change when slice live data has update
2. keep showing Output Switcher slice when media state is in "Pause"
   state

Bug: 247043239
Bug: 238715094
Bug: 204165377
Test: verified on device
Change-Id: Ic56a70f2f2835231519e2fccf0d2e649d41b106e