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.
throw new Error("Not implemented: createScripting");
  }
  static get supportsIntegratedFind() {
    return shadow(this, "supportsIntegratedFind", false);
  }
  static get supportsDocumentFonts() {
    return shadow(this, "supportsDocumentFonts", true);
  }
  static get supportedMouseWheelZoomModifierKeys() {
    return shadow(this, "supportedMouseWheelZoomModifierKeys", {
      ctrlKey: true,
      metaKey: true,
    });
  }
  static get isInAutomation() {
    return shadow(this, "isInAutomation", false);
  }
}
const PDFViewerApplication = {
  initialBookmark: document.location.hash.substring(1),
  _initializedCapability: createPromiseCapability(),
  _fellback: false,
  appConfig: null,
  pdfDocument: null,
  pdfLoadingTask: null,
  printService: null,
  
  pdfViewer: null,