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.
const appConfig = PDFViewerApplication.appConfig;
  let file;
  if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
    const queryString = document.location.search.substring(1);
    const params = parseQueryString(queryString);
    file = params.get("file") ?? AppOptions.get("defaultUrl");
    validateFileURL(file);
  } else if (PDFJSDev.test("MOZCENTRAL")) {
    file = window.location.href;
  } else if (PDFJSDev.test("CHROME")) {
    file = AppOptions.get("defaultUrl");
  }
  if (typeof PDFJSDev === "undefined" || PDFJSDev.test("GENERIC")) {
    const fileInput = document.createElement("input");
    fileInput.id = appConfig.openFileInputName;
    fileInput.className = "fileInput";
    fileInput.setAttribute("type", "file");
    fileInput.oncontextmenu = noContextMenuHandler;
    document.body.appendChild(fileInput);
    if (
      !window.File ||
      !window.FileReader ||
      !window.FileList ||