chore: remove dummy method

Author: bevzzz

src/main/java/io/weaviate/client6/v1/api/collections/data/ReferenceAddManyRequest.java

@@ -4,7 +4,6 @@
 import java.util.List;
 
 import io.weaviate.client6.v1.api.collections.CollectionHandleDefaults;
-import io.weaviate.client6.v1.internal.grpc.protocol.WeaviateProtoBatch;
 import io.weaviate.client6.v1.internal.json.JSON;
 import io.weaviate.client6.v1.internal.rest.Endpoint;
 import io.weaviate.client6.v1.internal.rest.SimpleEndpoint;
@@ -32,8 +31,4 @@ public static final Endpoint<ReferenceAddManyRequest, ReferenceAddManyResponse>
           return new ReferenceAddManyResponse(errors);
         });
   }
-
-  public static WeaviateProtoBatch.BatchReference buildReference(ObjectReference reference) {
-    return null;
-  }
 }