Merge "Notify source transport for upcoming handover" into tm-qpr-dev am: 5fb50336 am: aae09101

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/opt/telephony/+/19224118



Change-Id: I47808d4c2abfc9d6b646c9f483a70683a03b230d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>