Allow system access to overlay service

Test: manual
Bug: 37014702
Change-Id: Id43dc7a8506fe60015c2f82242ba45cf85d3e74b

public/service.te

@@ -97,7 +97,7 @@ type network_score_service, system_api_service, system_server_service, service_m
 type network_time_update_service, system_server_service, service_manager_type;
 type notification_service, app_api_service, ephemeral_app_api_service, system_server_service, service_manager_type;
 type otadexopt_service, system_server_service, service_manager_type;
-type overlay_service, system_server_service, service_manager_type;
+type overlay_service, system_api_service, system_server_service, service_manager_type;
 type package_service, app_api_service, ephemeral_app_api_service, system_server_service, service_manager_type;
 type permission_service, app_api_service, ephemeral_app_api_service, system_server_service, service_manager_type;
 type persistent_data_block_service, system_api_service, system_server_service, service_manager_type;