AudioService: Unmute Le Audio devices when activated

Since the mute state is not being stored individually for each device type and the volume level is, only volume level is restored on active audio device change and mute level can either be derived from the volume level (when reaches 0), be left unchanged from the previous device type, or unmuted automatically.
Leaving LE Audio devices muted can cause some issues with the additional manual unmuting and is inconsistent with the BT classic earbuds experience.

Bug: 273276001
Test: manual testing - mute when on speaker, then connect LE Audio earbuds
Change-Id: Ic6795092ec50befc5f796a844e552f4df9df6d8b