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.
if (!AppOptions.get("pdfBugEnabled")) {
      return;
    }
    const hash = document.location.hash.substring(1);
    if (!hash) {
      return;
    }
    const params = parseQueryString(hash),
      waitOn = [];
    if (params.get("disableworker") === "true") {
      waitOn.push(loadFakeWorker());
    }
    if (params.has("disablerange")) {
      AppOptions.set("disableRange", params.get("disablerange") === "true");
    }
    if (params.has("disablestream")) {
      AppOptions.set("disableStream", params.get("disablestream") === "true");
    }
    if (params.has("disableautofetch")) {
      AppOptions.set(
        "disableAutoFetch",
        params.get("disableautofetch") === "true"
      );
    }
    if (params.has("disablefontface")) {
      AppOptions.set(
        "disableFontFace",
        params.get("disablefontface") === "true"