Stop Scylla Manager task before deletion

Tasks that are running and are deleted contine their run.
This may prevent other tasks from being run if they are created and
started before deleted task finishes.

pkg/controller/manager/sync_action.go

@@ -358,7 +358,7 @@ type deleteTaskAction struct {
 }
 
 func (a *deleteTaskAction) Execute(ctx context.Context, client *managerclient.Client, status *scyllav1.ScyllaClusterStatus) error {
-	err := client.DeleteTask(ctx, a.clusterID, a.taskType, uuid.MustParse(a.taskID))
+	err := a.stopAndDeleteTask(ctx, client)
 
 	if a.taskType == "repair" {
 		filteredStatuses := status.Repairs[:0]
@@ -388,6 +388,21 @@ func (a *deleteTaskAction) Execute(ctx context.Context, client *managerclient.Cl
 	return err
 }
 
+func (a *deleteTaskAction) stopAndDeleteTask(ctx context.Context, client *managerclient.Client) error {
+	// StopTask is idempotent
+	err := client.StopTask(ctx, a.clusterID, a.taskType, uuid.MustParse(a.taskID), false)
+	if err != nil {
+		return fmt.Errorf("can't stop task %q: %w", a.taskID, err)
+	}
+
+	err = client.DeleteTask(ctx, a.clusterID, a.taskType, uuid.MustParse(a.taskID))
+	if err != nil {
+		return fmt.Errorf("can't delete task %q: %w", a.taskID, err)
+	}
+
+	return nil
+}
+
 func (a deleteTaskAction) String() string {
 	return fmt.Sprintf("delete task %q", a.taskID)
 }