Unmute audio streams for full volume device

Moving an audio device to full volume behavior ensures all audio strams
are at max volume. However muted audio streams remain muted.

Full volume devices do not allow mute changes, leaving streams that are
muted stuck in this state.

This adds to the logic turning streams to max volume to also unmute
streams if the device is in full volume behavior.

BUG: 160447552
Test: manual
Change-Id: Ic74108b7e2928f715d0b4773ab59284f3829eb22