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/domain/DomainApplicationDeleteFlow.java

@@ -66,7 +66,7 @@ public class DomainApplicationDeleteFlow
     // Don't allow deleting a sunrise application during landrush.
     if (existingResource.getPhase().equals(LaunchPhase.SUNRISE)
         && Registry.get(existingResource.getTld()).getTldState(now).equals(TldState.LANDRUSH)
-        && !superuser) {
+        && !isSuperuser) {
       throw new SunriseApplicationCannotBeDeletedInLandrushException();
     }
   }