[automerger skipped] DO NOT MERGE Add helper method in phone to get new carrier config key. am: e0aee3c0c0 am: 7a35940471 -s ours

am skip reason: subject contains skip directive

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/opt/telephony/+/24628058

Change-Id: Id761631bf177d53d28f7757290e92858eb140f01
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>