Increase the timeout when waiting for the downsampling to start

Author: gmarouli

x-pack/plugin/downsample/src/internalClusterTest/java/org/elasticsearch/xpack/downsample/DataStreamLifecycleDownsampleDisruptionIT.java

@@ -97,7 +97,7 @@ public void testDataStreamLifecycleDownsampleRollingRestart() throws Exception {
         ensureDownsamplingStatus(
             targetIndex,
             Set.of(IndexMetadata.DownsampleTaskStatus.STARTED, IndexMetadata.DownsampleTaskStatus.SUCCESS),
-            TimeValue.timeValueMillis(4500)
+            TimeValue.timeValueSeconds(6)
         );
 
         logger.info("-> Starting the disruption.");