Telecom:fix NPE problem in the CallSManager java file. am: e99bb8100a am: aeb4981143

Original change: https://android-review.googlesource.com/c/platform/packages/services/Telecomm/+/3081386

Change-Id: I09dbbc58971235556bb558ae2b0fba14b2514cf4
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>