Filter out non-a2dp or non-hearing Aid bluetooth device

- This CL before, disconnect group will show all disconnected
  device which will confuse user because output switcher only
  support a2dp or hearing aid device to transfer.

  This CL will filter out non-a2dp and non-hearing aid bluetooth
  device in disconnected group.
- Add test case

Bug: 154962266
Test: make -j42 RunSettingsLibRoboTests
Change-Id: Ifa927970b19a7cf7b32fcbe2093b285c718ba94f