Allow shell to change RKP properties

This way, we can change things like the RKP hostname or enablement
from the shell for tests.

Bug: 265196434
Test: manual (adb shell setprop ...)
Change-Id: Ib853eaf29b395705eba57d241df064152220457e
diff --git a/private/property.te b/private/property.te
index 4f806d4..4fd9bc3 100644
--- a/private/property.te
+++ b/private/property.te
@@ -632,6 +632,7 @@
   domain
   -init
   -remote_prov_app
+  -shell
 } remote_prov_prop:property_service set;
 
 neverallow {