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 percent = Math.round(level * 100);
    
    
    
    
    if (percent > this.loadingBar.percent || isNaN(percent)) {
      this.loadingBar.percent = percent;
      
      
      
      
      
      const disableAutoFetch = this.pdfDocument
        ? this.pdfDocument.loadingParams.disableAutoFetch
        : AppOptions.get("disableAutoFetch");
      if (disableAutoFetch && percent) {
        if (this.disableAutoFetchLoadingBarTimeout) {
          clearTimeout(this.disableAutoFetchLoadingBarTimeout);
          this.disableAutoFetchLoadingBarTimeout = null;
        }
        this.loadingBar.show();
        this.disableAutoFetchLoadingBarTimeout = setTimeout(() => {
          this.loadingBar.hide();
          this.disableAutoFetchLoadingBarTimeout = null;
        }, DISABLE_AUTO_FETCH_LOADING_BAR_TIMEOUT);
      }
    }
  },
  load(pdfDocument) {