Don't emit changed and stateChanged signal on OutputAreaModel._onListChanged

packages/outputarea/src/model.ts

@@ -442,7 +442,6 @@ class OutputAreaModel implements IOutputAreaModel {
       this._changeGuard = false;
     }
     this._changed.emit(args);
-    this._stateChanged.emit(void 0);
   }
 
   /**