Fix more kotlin nullable errors in services.permission am: 8bcfcd29 am: 623af71f

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/24588841



Change-Id: I16b67de950bac5d1cd77348ef42fb79ed3af1e7a
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>