Merge "Implement Observe Mode and Preferred Service event listeners with...

Merge "Implement Observe Mode and Preferred Service event listeners with functional callbacks." into main am: 7b40a103

Original change: https://android-review.googlesource.com/c/platform/frameworks/base/+/3323976



Change-Id: I8619192201034256d5bd2420ab55c13fb992f039
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>