Merge "Camera: Exit PreviewStreamSpacer when disconnecting stream" into tm-dev am: c3a3ee8362 am: 16f61fcb6e

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/av/+/18415584

Change-Id: I63ae3e891e0cddbac8ba7283f7fb24b2c94f7e95
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>