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

javatests/google/registry/model/EppResourceUtilsTest.java

@@ -87,6 +87,7 @@ public class EppResourceUtilsTest {
         sessionMetadata,
         new PasswordOnlyTransportCredentials(),
         false,
+        false,
         "<xml></xml>".getBytes(),
         null,
         clock)