Remove abuse contact requirement

The requirement will instead be enforced on registrar contact that is visible in WHOIS as abuse contact.

-------------
Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=154102111

java/google/registry/ui/server/registrar/RegistrarSettingsAction.java

@@ -269,8 +269,7 @@ public class RegistrarSettingsAction implements Runnable, JsonActionRunner.JsonA
         throw new ContactRequirementException(t);
       }
     }
-    ensurePhoneNumberNotRemovedForContactTypes(
-        oldContactsByType, newContactsByType, Type.ABUSE, Type.TECH);
+    ensurePhoneNumberNotRemovedForContactTypes(oldContactsByType, newContactsByType, Type.TECH);
   }
 
   /**