[Ambient Volume] Ambient volume icon

1. Click on the icon on the header will mute/unmute the remote devices in the same set if the remote devices are both mutable.
2. Show different icon when the value of the volume slide bars changed.

Flag: com.android.settingslib.flags.hearing_devices_ambient_volume_control
Bug: 357878944
Test: atest AmbientVolumePreferenceTest
Test: atest BluetoothDetailsAmbientVolumePreferenceControllerTest
Change-Id: I829c5e08f1456c8ef9936d0314045dc8da37cd95