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.
this._unblockDocumentLoadEvent();
    this._otherError(message, moreInfo);
  },
  /**
   * Show the error box; used for errors affecting e.g. only a single page.
   *
   * @param {string} message - A message that is human readable.
   * @param {Object} [moreInfo] - Further information about the error that is
   *                              more technical.  Should have a 'message' and
   *                              optionally a 'stack' property.
   */
  _otherError(message, moreInfo = null) {
    const moreInfoText = [
      this.l10n.get("error_version_info", {
        version: version || "?",
        build: build || "?",
      }),
    ];
    if (moreInfo) {
      moreInfoText.push(
        this.l10n.get("error_message", { message: moreInfo.message })
      );
      if (moreInfo.stack) {