stats_service: only disallow untrusted access

Allow device-specific domains to access stats_service. All access must
be done over proper APIs (StatsManager, AStatsManager) instead of
accessing the AIDL interfaces directly.

Test: build
Bug: 318788254
Change-Id: I98ddc1900350daf755372be7249f25a462e3242d
diff --git a/private/app_neverallows.te b/private/app_neverallows.te
index 5ea924a..ab8b8d5 100644
--- a/private/app_neverallows.te
+++ b/private/app_neverallows.te
@@ -258,6 +258,9 @@
 # Only privileged apps may find the incident service
 neverallow all_untrusted_apps incident_service:service_manager find;
 
+# Only privileged apps may find stats service
+neverallow all_untrusted_apps stats_service:service_manager find;
+
 # Do not allow untrusted app to read hidden system proprerties.
 # We do not include in the exclusions other normally untrusted applications such as mediaprovider
 #  due to the specific logging use cases.