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.
if (this.pdfDocument?.annotationStorage.size > 0) {
      this.save(options);
    } else {
      this.download(options);
    }
  },
  /**
   * For PDF documents that contain e.g. forms and javaScript, we should only
   * trigger the fallback bar once the user has interacted with the page.
   * @private
   */
  _delayedFallback(featureId) {