Amend networkstack sepolicy for testing

NetworkStack GTS tests need get network_watchlist_service and
system_config_service to test their APIs which are used by
module. But it will block by avc denied when trying to get
these services. Thus, amend networkstack sepolicy that can get
these services correctly.

Bug: 185309847
Test: Verify GTS test can get service correctly.
Change-Id: Icb18065e94d0026c3232cebb7d5eb39277fe7552
diff --git a/private/network_stack.te b/private/network_stack.te
index 9a22a19..09a98b5 100644
--- a/private/network_stack.te
+++ b/private/network_stack.te
@@ -23,7 +23,9 @@
 allow network_stack app_api_service:service_manager find;
 allow network_stack dnsresolver_service:service_manager find;
 allow network_stack netd_service:service_manager find;
+allow network_stack network_watchlist_service:service_manager find;
 allow network_stack radio_service:service_manager find;
+allow network_stack system_config_service:service_manager find;
 allow network_stack radio_data_file:dir create_dir_perms;
 allow network_stack radio_data_file:file create_file_perms;