Adding audio commands for hostSide CTS tests

Adding commands to enable/disable a surround mode and set
encodedSurroundMode.
These commands are used in hostSide test to verify the
MediaCapabilitiesMetrics.

Bug: 206615436
Test: atest android.cts.statsdatom.media.MediaCapabilitiesTests#testSurroundSoundCapabilities
Change-Id: I3dc8dcca381e27b114387a87fe460f019413f0e1