Remove unused import in TransportShardBulkAction

Accidentally left from backporting #44092

Author: rjernst

server/src/main/java/org/elasticsearch/action/bulk/TransportShardBulkAction.java

@@ -26,7 +26,6 @@
 import org.elasticsearch.ExceptionsHelper;
 import org.elasticsearch.action.ActionListener;
 import org.elasticsearch.action.ActionRunnable;
-import org.elasticsearch.action.ActionType;
 import org.elasticsearch.action.DocWriteRequest;
 import org.elasticsearch.action.DocWriteResponse;
 import org.elasticsearch.action.delete.DeleteRequest;