Add persist.sysui.notification.builder_extras_ovrd

Adds persist.sysui.notification.builder_extras_override property
and associated permissions, which will be used to flag guard
a change in core/...Notification.java.

Permissions are limited in scope to avoid unnecessary access.
Apps may need to read the flag (because Notification.java
is a core library), but setting should only be possible
internally (and via debug shell).

Test: manual flash+adb setprop/getprop
Bug: 169435530
Change-Id: I3f7e2220798d22c90f4326570732a52b0deeb54d
diff --git a/private/app.te b/private/app.te
index b6b4714..427d10d 100644
--- a/private/app.te
+++ b/private/app.te
@@ -46,6 +46,7 @@
 get_prop(appdomain, adbd_config_prop)
 get_prop(appdomain, dck_prop)
 get_prop(appdomain, persist_wm_debug_prop)
+get_prop(appdomain, persist_sysui_builder_extras_prop)
 
 # Allow ART to be configurable via device_config properties
 # (ART "runs" inside the app process)