static async cancelAllESTasks (req, res) {
    try {
      const { body: result } = await Db.taskCancel(undefined, req.query.cluster);
      return res.send(JSON.stringify({ success: true, text: result }));
    } catch (err) {
      console.log(`ERROR - ${req.method} /api/estasks/cancelall`, util.inspect(err, false, 50));
      return res.serverError(500, err.toString());
    }
  }
POST - /api/estasks/cancelall

Cancels all running OpenSearch/Elasticsearch tasks (admin only).
@name /estasks/cancelall
@returns {boolean} success - Whether the cancel all tasks operation was successful.
@returns {string} text - The success/error message to (optionally) display to the user.