[7.7][ML] Use non-zero timeout when force stopping DF analytics (elastic#56423) (elastic#56431)

We have been using a zero timeout in the case that DF analytics
is stopped. This may cause a timeout when we cancel, for example,
the reindex task.

This commit fixes this by using the default timeout instead.

Backport of elastic#56423

Author: dimitris-athanasiou

x-pack/plugin/core/src/main/java/org/elasticsearch/xpack/core/ml/action/StopDataFrameAnalyticsAction.java

@@ -33,12 +33,15 @@
 import java.util.HashSet;
 import java.util.Objects;
 import java.util.Set;
+import java.util.concurrent.TimeUnit;
 
 public class StopDataFrameAnalyticsAction extends ActionType<StopDataFrameAnalyticsAction.Response> {
 
     public static final StopDataFrameAnalyticsAction INSTANCE = new StopDataFrameAnalyticsAction();
     public static final String NAME = "cluster:admin/xpack/ml/data_frame/analytics/stop";
 
+    public static final TimeValue DEFAULT_TIMEOUT = new TimeValue(30, TimeUnit.SECONDS);
+
     private StopDataFrameAnalyticsAction() {
         super(NAME, StopDataFrameAnalyticsAction.Response::new);
     }
@@ -76,6 +79,7 @@ public static Request parseRequest(String id, XContentParser parser) {
 
         public Request(String id) {
             setId(id);
+            setTimeout(DEFAULT_TIMEOUT);
         }
 
         public Request(StreamInput in) throws IOException {

x-pack/plugin/ml/src/main/java/org/elasticsearch/xpack/ml/dataframe/DataFrameAnalyticsTask.java

@@ -37,6 +37,7 @@
 import org.elasticsearch.xpack.core.ml.MlTasks;
 import org.elasticsearch.xpack.core.ml.action.GetDataFrameAnalyticsStatsAction;
 import org.elasticsearch.xpack.core.ml.action.StartDataFrameAnalyticsAction;
+import org.elasticsearch.xpack.core.ml.action.StopDataFrameAnalyticsAction;
 import org.elasticsearch.xpack.core.ml.dataframe.DataFrameAnalyticsState;
 import org.elasticsearch.xpack.core.ml.dataframe.DataFrameAnalyticsTaskState;
 import org.elasticsearch.xpack.core.ml.job.messages.Messages;
@@ -105,7 +106,7 @@ public StatsHolder getStatsHolder() {
 
     @Override
     protected void onCancelled() {
-        stop(getReasonCancelled(), TimeValue.ZERO);
+        stop(getReasonCancelled(), StopDataFrameAnalyticsAction.DEFAULT_TIMEOUT);
         markAsCompleted();
     }