Merge "Migrate reigster service callback backend" am: ee0e6cd701 am: 044b5fc9eb am: 32a7daf625

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2424806

Change-Id: Id12b15e72ce89702f7bd73f0fea91eb60437eddf
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>