Since #12241 we have notifications for this when the user navigates away from the viewer, but we do not yet warn when switching documents, which means that if you call e.g. `PDFViewerApplication.open` with a new document (or directly call `BaseViewer.setDocument` when using the viewer components standalone) there won't be any warning about losing form data. This should be addressed.
handled = true;
        }
        if (
          !PDFViewerApplication.supportsIntegratedFind &&
          PDFViewerApplication.findBar.opened
        ) {
          PDFViewerApplication.findBar.close();
          handled = true;
        }
        break;
      case 40: 
      case 34: 
        
        if (pdfViewer.isVerticalScrollbarEnabled) {
          turnOnlyIfPageFit = true;
        }
        turnPage = 1;
        break;
      case 13: 
      case 32: 
        if (!isViewerInPresentationMode) {
          turnOnlyIfPageFit = true;
        }
        turnPage = 1;
        break;
      case 39: 
        
        if (pdfViewer.isHorizontalScrollbarEnabled) {
          turnOnlyIfPageFit = true;
        }