Merge "Fix unregistering callbacks" am: b6a2beb6

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Bluetooth/+/2052885



Change-Id: I6796e0935021a0ddead039f26070f0963192264d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>