Correcting license header on ResponseHandlingTest.java

Signed-off-by: Manan Rajotia <rajotia@amazon.com>

Author: Manan Rajotia

data-prepper-plugins/aws-lambda/src/test/java/org/opensearch/dataprepper/plugins/lambda/common/config/ResponseHandlingTest.java

@@ -1,6 +1,11 @@
 /*
  * Copyright OpenSearch Contributors
  * SPDX-License-Identifier: Apache-2.0
+ *
+ * The OpenSearch Contributors require contributions made to
+ * this file be licensed under the Apache-2.0 license or a
+ * compatible open source license.
+ *
  */
 
 package org.opensearch.dataprepper.plugins.lambda.common.config;