Add missing import

Author: felixbarny

x-pack/plugin/otel-data/src/main/java/org/elasticsearch/xpack/oteldata/otlp/datapoint/DataPointGroupingContext.java

@@ -26,6 +26,7 @@
 import org.elasticsearch.xpack.oteldata.otlp.tsid.ResourceTsidFunnel;
 import org.elasticsearch.xpack.oteldata.otlp.tsid.ScopeTsidFunnel;
 
+import java.util.ArrayList;
 import java.util.HashMap;
 import java.util.HashSet;
 import java.util.Iterator;