message: fixed single pdf bug with file unit
diff: @@ -411,7 +411,7 @@ export class DownloadController {
  }
  solutions += localUnit.toHtmlForSinglePDFSolutions() + '</div>';
  solCounter++;
  - } else {
  + } else if (localUnit.__t !== 'file') {
  solutions += localUnit.toHtmlForSinglePDFSolutions();
  }
  unitCounter++;
  