Automated g4 rollback of changelist 240574585.

*** Reason for rollback ***

The inconsistent class loading is breaking the tests

*** Original change description ***

Validate provided email addresses when creating a Registrar

***

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=241014945

java/google/registry/model/registrar/RegistrarContact.java

@@ -18,7 +18,6 @@ import static com.google.common.base.Preconditions.checkNotNull;
 import static com.google.common.collect.ImmutableSet.toImmutableSet;
 import static com.google.common.collect.Sets.difference;
 import static google.registry.model.ofy.ObjectifyService.ofy;
-import static google.registry.model.registrar.Registrar.checkValidEmail;
 import static google.registry.util.CollectionUtils.nullToEmptyImmutableSortedCopy;
 import static java.util.stream.Collectors.joining;
 
@@ -297,7 +296,7 @@ public class RegistrarContact extends ImmutableObject implements Jsonifiable {
     @Override
     public RegistrarContact build() {
       checkNotNull(getInstance().parent, "Registrar parent cannot be null");
-      checkValidEmail(getInstance().emailAddress);
+      checkNotNull(getInstance().emailAddress, "Email address cannot be null");
       return cloneEmptyToNull(super.build());
     }