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.
case 82: 
        PDFViewerApplication.rotatePages(90);
        break;
      case 115: 
        PDFViewerApplication.pdfSidebar.toggle();
        break;
    }
    if (
      turnPage !== 0 &&
      (!turnOnlyIfPageFit || pdfViewer.currentScaleValue === "page-fit")
    ) {
      if (turnPage > 0) {
        pdfViewer.nextPage();
      } else {
        pdfViewer.previousPage();
      }
      handled = true;
    }
  }
  
  if (cmd === 4) {
    switch (evt.keyCode) {
      case 13: 
      case 32: 
        if (
          !isViewerInPresentationMode &&
          pdfViewer.currentScaleValue !== "page-fit"
        ) {
          break;
        }