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.
eventBus._on("lastpage", webViewerLastPage);
    eventBus._on("nextpage", webViewerNextPage);
    eventBus._on("previouspage", webViewerPreviousPage);
    eventBus._on("zoomin", webViewerZoomIn);
    eventBus._on("zoomout", webViewerZoomOut);
    eventBus._on("zoomreset", webViewerZoomReset);
    eventBus._on("pagenumberchanged", webViewerPageNumberChanged);
    eventBus._on("scalechanged", webViewerScaleChanged);
    eventBus._on("rotatecw", webViewerRotateCw);
    eventBus._on("rotateccw", webViewerRotateCcw);
    eventBus._on("optionalcontentconfig", webViewerOptionalContentConfig);
    eventBus._on("switchscrollmode", webViewerSwitchScrollMode);
    eventBus._on("scrollmodechanged", webViewerScrollModeChanged);
    eventBus._on("switchspreadmode", webViewerSwitchSpreadMode);
    eventBus._on("spreadmodechanged", webViewerSpreadModeChanged);
    eventBus._on("documentproperties", webViewerDocumentProperties);
    eventBus._on("findfromurlhash", webViewerFindFromUrlHash);
    eventBus._on("updatefindmatchescount", webViewerUpdateFindMatchesCount);
    eventBus._on("updatefindcontrolstate", webViewerUpdateFindControlState);
    if (AppOptions.get("pdfBug")) {
      _boundEvents.reportPageStatsPDFBug = reportPageStatsPDFBug;
      eventBus._on("pagerendered", _boundEvents.reportPageStatsPDFBug);
      eventBus._on("pagechanging", _boundEvents.reportPageStatsPDFBug);
    }
    if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
      eventBus._on("fileinputchange", webViewerFileInputChange);
      eventBus._on("openfile", webViewerOpenFile);
    }
  },
  bindWindowEvents() {