Decouple superuser from SessionMetadata

Superuser should only be settable via the tool (see []
which is merged in here but not diffbased, and which removes
the implicit superuser for CharlestonRoad). It is a property
of the request, not of the session (there are no sessions in the tool).
-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=125204707

java/google/registry/flows/host/HostDeleteFlow.java

@@ -77,7 +77,7 @@ public class HostDeleteFlow extends ResourceAsyncDeleteFlow<HostResource, Builde
             DeleteEppResourceAction.PARAM_REQUESTING_CLIENT_ID,
             getClientId(),
             DeleteEppResourceAction.PARAM_IS_SUPERUSER,
-            Boolean.toString(superuser)),
+            Boolean.toString(isSuperuser)),
         RegistryEnvironment.get().config().getAsyncDeleteFlowMapreduceDelay());
   }