Support @EnforcePermission annotation

Update RequiresPermissionChecker to support a method annotated with
@EnforcePermission. If encountered, we assume that the implementation is
enforcing the declared permissions (this is verified by another linter).

Bug: 239369037
Test: atest --host error_prone_android_framework_test
Change-Id: I25deb47acc1259a1171954aeebd72eb60f01fc49