### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/master/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/master/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a feature request that matches the one I want to file, without success.

### Electron Version

13.1.7

### What operating system are you using?

Windows

### Operating System Version

Windows 10 version 20H2

### What arch are you using?

x64

### Last Known Working Electron version

12.0.15

### Expected Behavior

Checking `navigator.userAgentData` in Chrome 91 returns an array of brands appropriately. Electron 13/14 do not return anything.

This appears to then become a problem for my situation. I am posting a form with hidden variables to a third-party vendor I work with. This form post ultimately loads an iframe.

Expected: As it does in Chrome 91, load the iframe from this third-party vendor.

### Actual Behavior

A header of "sec-ch-ua" is included in the request to the third-party vendor and it is blank. They are rejecting the post because of an invalid header. I suspect this is because Chrome 13/14 does not make this hint data made available correctly.

I tried loading various sites in Chrome 91 that do load brand names in Electron 13/14 and they are empty if you review `navigator.userAgentData`.

### Testcase Gist URL

_No response_

### Additional Information

_No response_
shell/browser/electron_browser_client.h
void RenderProcessReady(content::RenderProcessHost* host) override;
  void RenderProcessExited(
      content::RenderProcessHost* host,
      const content::ChildProcessTerminationInfo& info) override;
 private:
  content::SiteInstance* GetSiteInstanceFromAffinity(
      content::BrowserContext* browser_context,
      const GURL& url,
      content::RenderFrameHost* rfh) const;
  bool IsRendererSubFrame(int process_id) const;
  
  std::map<int, content::WebContents*> pending_processes_;
  std::set<int> renderer_is_subframe_;
  std::unique_ptr<PlatformNotificationService> notification_service_;
  std::unique_ptr<NotificationPresenter> notification_presenter_;
  Delegate* delegate_ = nullptr;
  std::string user_agent_override_ = "";
  
  
  uint64_t next_id_ = 0;
  std::unique_ptr<ElectronSerialDelegate> serial_delegate_;
  std::unique_ptr<ElectronBluetoothDelegate> bluetooth_delegate_;
  std::unique_ptr<ElectronHidDelegate> hid_delegate_;
#if BUILDFLAG(IS_MAC)
  ElectronBrowserMainParts* browser_main_parts_ = nullptr;
#endif
};
}  
#endif