sepolicy: allow vendor system native experiments property

Grant system_server and flags_health_check permission to set the
properties that correspond to vendor system native experiments.

Bug: 226456604
Test: Build
Change-Id: Ib2420cf6eaf1645e7f938db32c93d085dd8950a3
diff --git a/private/property.te b/private/property.te
index 834d2df..14221af 100644
--- a/private/property.te
+++ b/private/property.te
@@ -46,6 +46,7 @@
 system_internal_prop(virtualizationservice_prop)
 
 # Properties which can't be written outside system
+system_restricted_prop(device_config_vendor_system_native_prop)
 system_restricted_prop(device_config_virtualization_framework_native_prop)
 
 ###