Add selinux policies for network stack service

The policies allow the system server to register a network_stack_service
used to communicate with the network stack process.

Test: atest FrameworksNetTests
Bug: b/112869080
Change-Id: Ib9b7d9150fe4afcce03c8b3dbb36b81c67e39366
diff --git a/private/compat/27.0/27.0.ignore.cil b/private/compat/27.0/27.0.ignore.cil
index 994fb07..88cf5d6 100644
--- a/private/compat/27.0/27.0.ignore.cil
+++ b/private/compat/27.0/27.0.ignore.cil
@@ -110,6 +110,7 @@
     mnt_product_file
     mnt_vendor_file
     network_stack
+    network_stack_service
     network_watchlist_data_file
     network_watchlist_service
     overlayfs_file