Fix 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:6687a2caee0e1ab853c080924a5985fb5be71e28)
Merged-In: Iead08db297fa20963df7ee83b19d5ac76d0d4846
Change-Id: Iead08db297fa20963df7ee83b19d5ac76d0d4846