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.
case 70: 
        if (!PDFViewerApplication.supportsIntegratedFind && !evt.shiftKey) {
          PDFViewerApplication.findBar.open();
          handled = true;
        }
        break;
      case 71: 
        if (!PDFViewerApplication.supportsIntegratedFind) {
          const { state } = PDFViewerApplication.findController;
          if (state) {
            const eventState = Object.assign(Object.create(null), state, {
              source: window,
              type: "again",
              findPrevious: cmd === 5 || cmd === 12,
            });
            eventBus.dispatch("find", eventState);
          }
          handled = true;
        }
        break;
      case 61: 
      case 107: 
      case 187: 
      case 171: 
        if (!isViewerInPresentationMode) {
          PDFViewerApplication.zoomIn();
        }
        handled = true;
        break;
      case 173: