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.
window.addEventListener("hashchange", _boundEvents.windowHashChange);
    window.addEventListener("beforeprint", _boundEvents.windowBeforePrint);
    window.addEventListener("afterprint", _boundEvents.windowAfterPrint);
    window.addEventListener(
      "updatefromsandbox",
      _boundEvents.windowUpdateFromSandbox
    );
  },
  unbindEvents() {
    const { eventBus, _boundEvents } = this;
    eventBus._off("resize", webViewerResize);
    eventBus._off("hashchange", webViewerHashchange);
    eventBus._off("beforeprint", _boundEvents.beforePrint);
    eventBus._off("afterprint", _boundEvents.afterPrint);
    eventBus._off("pagerendered", webViewerPageRendered);
    eventBus._off("updateviewarea", webViewerUpdateViewarea);
    eventBus._off("pagechanging", webViewerPageChanging);
    eventBus._off("scalechanging", webViewerScaleChanging);
    eventBus._off("rotationchanging", webViewerRotationChanging);
    eventBus._off("sidebarviewchanged", webViewerSidebarViewChanged);
    eventBus._off("pagemode", webViewerPageMode);
    eventBus._off("namedaction", webViewerNamedAction);
    eventBus._off("presentationmodechanged", webViewerPresentationModeChanged);
    eventBus._off("presentationmode", webViewerPresentationMode);
    eventBus._off("print", webViewerPrint);
    eventBus._off("download", webViewerDownload);
    eventBus._off("save", webViewerSave);
    eventBus._off("firstpage", webViewerFirstPage);
    eventBus._off("lastpage", webViewerLastPage);
    eventBus._off("nextpage", webViewerNextPage);