### Preflight Checklist
<!-- Please ensure you've completed the following steps by replacing [ ] with [x]-->

* [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 for an issue that matches the one I want to file, without success.

### Issue Details

* **Electron Version:**
  * 8.0.0
* **Operating System:**
  * Windows 10 Pro (1709)

### Expected Behavior
Using Notification API in main process with `timeoutType: 'never` I expected that the notification disappears only when the user clicks on it.  

### Actual Behavior
After few seconds the notification disappers.

### To Reproduce

```
  const newNotification = new Notification({title: 'I am a main process Notification!', timeoutType: 'never'})
  newNotification.show()
```

```sh
$ git clone https://github.com/p-fusi/electron-quick-start -b master
$ npm install
$ npm run start
```


shell/browser/notifications/win/windows_toast_notification.cc
} else {
    auto* presenter_win = static_cast<NotificationPresenterWin*>(presenter());
    std::wstring icon_path =
        presenter_win->SaveIconToFilesystem(options.icon, options.icon_url);
    REPORT_AND_RETURN_IF_FAILED(
        GetToastXml(toast_manager_.Get(), options.title, options.msg, icon_path,
                    options.timeout_type, options.silent, &toast_xml),
        "XML: Failed to create XML document");
  }
  ScopedHString toast_str(
      RuntimeClass_Windows_UI_Notifications_ToastNotification);
  if (!toast_str.success()) {
    NotificationFailed("Creating ScopedHString failed");
    return E_FAIL;
  }
  ComPtr<ABI::Windows::UI::Notifications::IToastNotificationFactory>
      toast_factory;
  REPORT_AND_RETURN_IF_FAILED(
      Windows::Foundation::GetActivationFactory(toast_str, &toast_factory),
      "WinAPI: GetActivationFactory failed");
  REPORT_AND_RETURN_IF_FAILED(toast_factory->CreateToastNotification(
                                  toast_xml.Get(), &toast_notification_),
                              "WinAPI: CreateToastNotification failed");
  REPORT_AND_RETURN_IF_FAILED(SetupCallbacks(toast_notification_.Get()),
                              "WinAPI: SetupCallbacks failed");
  REPORT_AND_RETURN_IF_FAILED(toast_notifier_->Show(toast_notification_.Get()),
                              "WinAPI: Show failed");
  return S_OK;
}
HRESULT WindowsToastNotification::GetToastXml(