Audio : Fix a few minor issues with stream switcher class am: 035beba203 am: f901f6a465 am: e54466ff88 am: 2ce73f1649 am: 0bb1891b1d

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

Change-Id: Ic4012049bf65804b8105d39418b7ab3e4fde2c48
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>