Mute ML upgrade test (#30458)

It fails fairly frequently. Some ML expert will look soon.

Author: alpar-t

x-pack/qa/rolling-upgrade/src/test/java/org/elasticsearch/upgrades/UpgradeClusterClientYamlTestSuiteIT.java

@@ -7,6 +7,8 @@
 
 import com.carrotsearch.randomizedtesting.annotations.ParametersFactory;
 import com.carrotsearch.randomizedtesting.annotations.TimeoutSuite;
+
+import org.apache.lucene.util.LuceneTestCase;
 import org.apache.lucene.util.TimeUnits;
 import org.elasticsearch.Version;
 import org.elasticsearch.client.Response;
@@ -32,6 +34,7 @@
 import static org.hamcrest.Matchers.is;
 
 @TimeoutSuite(millis = 5 * TimeUnits.MINUTE) // to account for slow as hell VMs
+@LuceneTestCase.AwaitsFix(bugUrl = "https://github.com/elastic/elasticsearch/issues/30456")
 public class UpgradeClusterClientYamlTestSuiteIT extends ESClientYamlSuiteTestCase {
 
     /**