Increase timeout in MlDistributedFailureIT (#58997)

Doubles the timeout on the ensureStableClusterOnAllNodes method to 60s
to account for v slow ci

x-pack/plugin/ml/src/internalClusterTest/java/org/elasticsearch/xpack/ml/integration/MlDistributedFailureIT.java

@@ -543,8 +543,6 @@ public class MlDistributedFailureIT extends BaseMlIntegTestCase {
     }
 
     private void ensureStableClusterOnAllNodes(int nodeCount) {
-        for (String nodeName : internalCluster().getNodeNames()) {
-            ensureStableCluster(nodeCount, nodeName);
-        }
+        ensureStableCluster(nodeCount, TimeValue.timeValueSeconds(60));
     }
 }