Cleanup for linter

Signed-off-by: Jonah Calvo <caljonah@amazon.com>

Author: Jonah Calvo

data-prepper-plugins/opensearch/src/main/java/org/opensearch/dataprepper/plugins/sink/opensearch/index/DataStreamDetector.java

@@ -17,7 +17,6 @@
 import org.slf4j.LoggerFactory;
 
 import java.io.IOException;
-import java.util.concurrent.ConcurrentHashMap;
 
 /**
  * Utility class to detect if an index name refers to a Data Stream