### 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
ABI::Windows::UI::Notifications::IToastNotificationManagerStatics*
        toastManager,
    const std::wstring& title,
    const std::wstring& msg,
    const std::wstring& icon_path,
    const std::wstring& timeout_type,
    bool silent,
    IXmlDocument** toast_xml) {
  ABI::Windows::UI::Notifications::ToastTemplateType template_type;
  if (title.empty() || msg.empty()) {
    
    template_type =
        icon_path.empty()
            ? ABI::Windows::UI::Notifications::ToastTemplateType_ToastText01
            : ABI::Windows::UI::Notifications::
                  ToastTemplateType_ToastImageAndText01;
    REPORT_AND_RETURN_IF_FAILED(
        toast_manager_->GetTemplateContent(template_type, toast_xml),
        "XML: Fetching XML ToastImageAndText01 template failed");
    std::wstring toastMsg = title.empty() ? msg : title;
    
    toastMsg = toastMsg.empty() ? L"[no message]" : toastMsg;
    REPORT_AND_RETURN_IF_FAILED(
        SetXmlText(*toast_xml, toastMsg),
        "XML: Filling XML ToastImageAndText01 template failed");
  } else {
    
    template_type =
        icon_path.empty()
            ? ABI::Windows::UI::Notifications::ToastTemplateType_ToastText02