Merge "Add signal strength callback" into udc-qpr-dev am: 8a0a99cb am: 3c43f4e7

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/opt/telephony/+/23594442



Change-Id: Ib20c11d90f55775699a41dd92f620cc54a39f6af
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>