Add prop to control PM appcompat

We need to explicitly disable app compat so that apk
alignment status can be detected.

Test: m
Bug: 381949453
Change-Id: Ief0df075a7b65c8c2300c5f9fed57b16092b70b9
diff --git a/private/system_server.te b/private/system_server.te
index a764df4..9528071 100644
--- a/private/system_server.te
+++ b/private/system_server.te
@@ -823,6 +823,9 @@
 # staged flag properties
 set_prop(system_server, next_boot_prop)
 
+# Allow system server to read pm.16kb.app_compat.disabled
+get_prop(system_server, pm_16kb_app_compat_prop)
+
 # Allow query ART device config properties
 get_prop(system_server, device_config_runtime_native_boot_prop)
 get_prop(system_server, device_config_runtime_native_prop)