Remove callback upon MediaSession#release am: 3cfa79c53c am: b68a7b7822

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24464032

Change-Id: I91eb4426bc921af85d89298fc1c6e176f00a47bf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>