dialogflow: clear no input timer on caller hangup

lib/tasks/dialogflow/index.js

@@ -88,6 +88,8 @@ class Dialogflow extends Task {
       this.ep.removeCustomEventListener('dialogflow::end_of_utterance');
       this.ep.removeCustomEventListener('dialogflow::error');
 
+      this._clearNoinputTimer();
+
       if (!this.reportedFinalAction) this.performAction({dialogflowResult: 'caller hungup'})
         .catch((err) => this.logger.error({err}, 'dialogflow - error w/ action webook'));