Seperated ambient mute state for different devices

Store seperated mute state for each devices instead of having an unified mute state. To reflect the mute icon behavior, if one device is mutable then the icon is mutable(clickable); if all devices are muted then the icon will show muted icon.

Flag: EXEMPT bugfix
Bug: 412968925
Test: manually test with real devices
Test: atest AmbientVolumePreferenceTest
Change-Id: Ib25fd1e1efff34fb6cf1b1f0e192fe7b5bb3c644