Merge "Protect against NPE during RTT call sessions" am: 6e6efb17

Original change: https://android-review.googlesource.com/c/platform/frameworks/opt/telephony/+/2107012



Change-Id: I54c4aff4d521fe4839d349f2685154d9cda128a5
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>