Fix null pointer crash in AIDL radio HAL VTS am: cf892db1ef

Original change: https://googleplex-android-review.googlesource.com/c/platform/hardware/interfaces/+/24133137

Change-Id: I8808c3c3ea0d30914597a5199c15bc3eddc9e723
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>