When using viewer.js code in an iframe (`web/viewer.html?file=my.pdf"`) and getting a load error like `Error: file origin does not match viewer's` how do I catch this error?  The console reports `app.js:2140 Uncaught (in promise) Error: file origin does not match viewer's`.  I have setup the load listener and am using the `PDFViewerApplication.initializedPromise`.  I was hoping the `PDFViewerApplication.initializedPromise` would reject, but it does not.  I could not find an eventbus event to listen to specifically for load errors either.

I would like to programmatically detect such load errors and dynamically remove the iframe hosting the pdf viewer and instead replace it with my own error messaging.  I can't figure out how to do that.

Configuration:
- Any, but testing on Chrome 97.0.4692.71 64-bit
- Ubuntu 20.04
- PDF.js version:  v2.12.313
- Is a browser extension: No

Steps to reproduce the problem:
1.  Purposely try to load a PDF in a way that would cause the `app.js:2140 Uncaught (in promise) Error: file origin does not match viewer's` error.
annotationMode: AppOptions.get("annotationMode"),
      imageResourcesPath: AppOptions.get("imageResourcesPath"),
      enablePrintAutoRotate: AppOptions.get("enablePrintAutoRotate"),
      useOnlyCssZoom: AppOptions.get("useOnlyCssZoom"),
      maxCanvasPixels: AppOptions.get("maxCanvasPixels"),
      enablePermissions: AppOptions.get("enablePermissions"),
    });
    pdfRenderingQueue.setViewer(this.pdfViewer);
    pdfLinkService.setViewer(this.pdfViewer);
    pdfScriptingManager.setViewer(this.pdfViewer);
    this.pdfThumbnailViewer = new PDFThumbnailViewer({
      container: appConfig.sidebar.thumbnailView,
      eventBus,
      renderingQueue: pdfRenderingQueue,
      linkService: pdfLinkService,
      l10n: this.l10n,
    });
    pdfRenderingQueue.setThumbnailViewer(this.pdfThumbnailViewer);
    
    
    if (!this.isViewerEmbedded && !AppOptions.get("disableHistory")) {
      this.pdfHistory = new PDFHistory({
        linkService: pdfLinkService,
        eventBus,
      });
      pdfLinkService.setHistory(this.pdfHistory);
    }
    if (!this.supportsIntegratedFind) {
      this.findBar = new PDFFindBar(appConfig.findBar, eventBus, this.l10n);
    }