Add ro.audio.ihaladaptervendorextension_enabled property

This property is used by libaudiohal@aidl to detect whether
the system_ext partition provides an instance of
IHalAdapterVendorExtension. This is a "system internal"
property because it belongs to `system_ext`.

Bug: 323989070
Test: atest audiorouting_test
Ignore-AOSP-First: coupled with Pixel change, will upstream
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:17406cd0a723cb89a03705709ec78d37b3d66042)
Merged-In: I81267da070958a70f2f3c4882718cac4600e3476
Change-Id: I81267da070958a70f2f3c4882718cac4600e3476
diff --git a/private/property.te b/private/property.te
index 38e69bb..d21df55 100644
--- a/private/property.te
+++ b/private/property.te
@@ -44,6 +44,7 @@
 system_internal_prop(setupwizard_prop)
 system_internal_prop(snapuserd_prop)
 system_internal_prop(system_adbd_prop)
+system_internal_prop(system_audio_config_prop)
 system_internal_prop(timezone_metadata_prop)
 system_internal_prop(traced_perf_enabled_prop)
 system_internal_prop(uprobestats_start_with_config_prop)