Merge "audio: Make StreamDescriptor::Command a union" am: 2b68543625 am: 224a3b1755 am: 2b74484576

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2296167

Change-Id: Ic8da95d66db1321a313a680df13ff23ba8153def
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>