BUG: Guard qtmodelview before calling function

So here is the story:

Dear @john.tourtellott fixed the undocked dock widget so that we would explicitly close the operation dialog. But when recording the importExport2dm test, before clicking Close data in menu the mouse would come across qtModelEntityItem which triggers entity to be highlighted. Since the dock widget has been deleted, there is no qtModelView to be hightlighted which results in a segfault.