Audio : Fix a few minor issues with stream switcher class am: 035beba203 am: f901f6a465 am: e54466ff88

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2680756

Change-Id: I70d9e49ccb9430a283acd9b501f78737193847aa
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>