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### Issue Details

* **Electron Version:**
  * 9.0.0-beta.18 x86
* **Operating System:**
  * win7 x64 sp1
* **Last Known Working Electron version:**
  * 4.2.9 x86

### Expected Behavior
Per the docs and the original implementation, `acceptLanguages` param should be controlling the Accept-Language header.

https://github.com/electron/electron/blob/4-2-x/atom/browser/api/atom_api_session.cc#L612
https://www.electronjs.org/docs/api/session#sessetuseragentuseragent-acceptlanguages

### Actual Behavior
`acceptLanguages` param is ignored, Accept-Language remains at its default.

### To Reproduce
- the current user os (win7) lang is "en-US"
- run the following app in 4.2 and 9.0
- inspect the request in the renderer devtools
- in 4.2, Accept-Language is "fr"
- in 9.0 it's "en-US"

```js
'use strict';

const {app, BrowserWindow} = require('electron');

let win;

app.once('ready', () => {

  win = new BrowserWindow({
    webPreferences: {
      nodeIntegration: false
    }
  });

  win.webContents.session.setUserAgent('', 'fr');

  win.webContents.openDevTools({mode: 'right'});
  win.loadURL('about:blank');
  setTimeout(() => win.loadURL('https://example.org/'), 3000);

});
```

### Additional Information
The original implementation of setUserAgent was removed at some point and it was later re-implemented by #20014 without acceptLanguages  support.

shell/browser/api/electron_api_session.cc
auto* command_line = base::CommandLine::ForCurrentProcess();
  network::mojom::HttpAuthDynamicParamsPtr auth_dynamic_params =
      network::mojom::HttpAuthDynamicParams::New();
  auth_dynamic_params->server_allowlist = domains;
  auth_dynamic_params->enable_negotiate_port =
      command_line->HasSwitch(electron::switches::kEnableAuthNegotiatePort);
  auth_dynamic_params->ntlm_v2_enabled =
      !command_line->HasSwitch(electron::switches::kDisableNTLMv2);
  content::GetNetworkService()->ConfigureHttpAuthPrefs(
      std::move(auth_dynamic_params));
}
void Session::SetUserAgent(const std::string& user_agent,
                           gin::Arguments* args) {
  browser_context_->SetUserAgent(user_agent);
  content::BrowserContext::GetDefaultStoragePartition(browser_context_.get())
      ->GetNetworkContext()
      ->SetUserAgent(user_agent);
}
std::string Session::GetUserAgent() {