[MTE] Add property to specify default MTE mode for apps.

Bug: 216305376
Change-Id: I9374c8681510037279deaf3e5ae011e8f9111f17
diff --git a/private/property_contexts b/private/property_contexts
index 7106a51..7d75a3b 100644
--- a/private/property_contexts
+++ b/private/property_contexts
@@ -708,6 +708,7 @@
 # shell-only props for ARM memory tagging (MTE).
 arm64.memtag. u:object_r:arm64_memtag_prop:s0 prefix string
 persist.arm64.memtag.default u:object_r:arm64_memtag_prop:s0 exact string
+persist.arm64.memtag.app_default u:object_r:arm64_memtag_prop:s0 exact string
 
 net.redirect_socket_calls.hooked u:object_r:socket_hook_prop:s0 exact bool