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 (params.has("disablehistory")) {
      AppOptions.set("disableHistory", params.get("disablehistory") === "true");
    }
    if (params.has("verbosity")) {
      AppOptions.set("verbosity", params.get("verbosity") | 0);
    }
    if (params.has("textlayer")) {
      switch (params.get("textlayer")) {
        case "off":
          AppOptions.set("textLayerMode", TextLayerMode.DISABLE);
          break;
        case "visible":
        case "shadow":
        case "hover":
          const viewer = this.appConfig.viewerContainer;
          viewer.classList.add(`textLayer-${params.get("textlayer")}`);
          break;
      }
    }
    if (params.has("pdfbug")) {
      AppOptions.set("pdfBug", true);
      AppOptions.set("fontExtraProperties", true);
      const enabled = params.get("pdfbug").split(",");
      waitOn.push(initPDFBug(enabled));
    }
    
    if (
      (typeof PDFJSDev === "undefined" ||