Add TODO comment as per review comment

Author: pawankartik-elastic

server/src/internalClusterTest/java/org/elasticsearch/search/ccs/CpsDoesNotUseSkipUnavailableIT.java

@@ -30,6 +30,7 @@
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertAcked;
 import static org.elasticsearch.test.hamcrest.ElasticsearchAssertions.assertResponse;
 
+// TODO: Move this test to the Serverless repo once the IT framework is ready there.
 public class CpsDoesNotUseSkipUnavailableIT extends AbstractMultiClustersTestCase {
     private static final String LINKED_CLUSTER_1 = "cluster-a";