Merge "Track last known RAT in voice call." into tm-qpr-dev am: 2a29f0cf am: b0340b9c

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/opt/telephony/+/19748419



Change-Id: I797b407c922afa9c6e47935cf6e7dbc1f8d882d8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>