Merge "Add nullability support for CarrierConfigLoader class" am: b6e8018d56

Original change: https://android-review.googlesource.com/c/platform/packages/services/Telephony/+/2106936

Change-Id: Iabac708c275a328ba97a496d5279865ffdeea137
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>