Flatten the domain transfer flows

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=133906420

java/google/registry/model/transfer/TransferResponse.java

@@ -58,6 +58,10 @@ public abstract class TransferResponse extends BaseTransferObject implements Res
     @XmlElement(name = "exDate")
     DateTime extendedRegistrationExpirationTime;
 
+    public DateTime getExtendedRegistrationExpirationTime() {
+      return extendedRegistrationExpirationTime;
+    }
+
     /** Builder for {@link DomainTransferResponse}. */
     public static class Builder
         extends BaseTransferObject.Builder<DomainTransferResponse, Builder> {