Fix more kotlin nullable errors in services.permission

Fix kotlin nullable errors that were exposed by setting the retention
of android.annotation.NonNull and android.annotation.Nullable to
class retention.

Bug: 294110802
Test: builds
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:8bcfcd296c80dacb4b387dada06b8303e61e520a)
Merged-In: I74b2b7570adf025cf8ec3ea105eb06ea22c7d30e
Change-Id: I74b2b7570adf025cf8ec3ea105eb06ea22c7d30e