Follow up with issue: https://github.com/mozilla/pdf.js/issues/14146
Merged pull req: https://github.com/mozilla/pdf.js/pull/14189

Attach (recommended) or Link to PDF file here:
https://bug1708641.bmoattachments.org/attachment.cgi?id=9219459

- This popup appears because JS is enabled;
- And because the pdf contains some unsupported features (e.g. XFA);

Configuration:
- Firefox Nightly & Chrome
- macOS Big Sur 11.6

Steps to reproduce the problem:
1. Run gulp server
2. Open attached pdf

What is the expected behavior? 
No popup on open

What went wrong?
![error](https://user-images.githubusercontent.com/76935202/139354112-707887a2-a6a1-43a9-a92e-45d57c48206a.jpg)



constructor(data) {
    super(data);
    this._constants = null;
    this._focusRect = true;
    this._fs = null;
    this._language = App._getLanguage(data.language);
    this._openInPlace = false;
    this._platform = App._getPlatform(data.platform);
    this._runtimeHighlight = false;
    this._runtimeHighlightColor = ["T"];
    this._thermometer = null;
    this._toolbar = false;
    this._document = data._document;
    this._proxyHandler = data.proxyHandler;
    this._objects = Object.create(null);
    this._eventDispatcher = new EventDispatcher(
      this._document,
      data.calculationOrder,
      this._objects
    );
    this._timeoutIds = new WeakMap();
    if (typeof FinalizationRegistry !== "undefined") {