Merge "MediaCas: Release cas resource only when all sessions are closed" into main am: e9e7e78f65 am: 89d3bb5a1c

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3016424

Change-Id: I792a8f3f03bc9372f9f5cdb84dd5d09130d8b6fd
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>