fix: add return value for handler to end command

src/utils/jensen.js

@@ -823,6 +823,7 @@ Jensen.prototype.getFile = async function (filename, length, ondata, onprogress)
       clearEventAndTask();
       Logger.info('jensen', 'getFile', 'file download fail.');
       ondata('fail');
+      return 'fail';
     }
   };
   this.onreceive = onprogress;