Remove as-of date from argument list for extra create flow logic

Lai points out that, for creation, the as-of date should always be equal to the creation time. And, in fact, there was a check to throw an exception if that is not the case. So it's more straightforward just to remove that argument entirely.

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=138783711

javatests/google/registry/model/domain/TestExtraLogicManager.java

@@ -198,7 +198,6 @@ public class TestExtraLogicManager implements RegistryExtraFlowLogic {
   public void performAdditionalDomainCreateLogic(
       DomainResource domain,
       String clientId,
-      DateTime asOfDate,
       int years,
       EppInput eppInput,
       HistoryEntry historyEntry) throws EppException {