Bump xmldom and react-native-windows in /NotificationHubSample/app

Removes [xmldom](https://github.com/xmldom/xmldom). It's no longer used after updating ancestor dependency [react-native-windows](https://github.com/microsoft/react-native-windows/tree/HEAD/vnext). These dependencies need to be updated together.


Removes `xmldom`

Updates `react-native-windows` from 0.63.5 to 0.63.41
- [Release notes](https://github.com/microsoft/react-native-windows/releases)
- [Changelog](https://github.com/microsoft/react-native-windows/blob/main/vnext/CHANGELOG.json)
- [Commits](https://github.com/microsoft/react-native-windows/commits/HEAD/vnext)

---
updated-dependencies:
- dependency-name: xmldom
  dependency-type: indirect
- dependency-name: react-native-windows
  dependency-type: direct:production
...

Signed-off-by: dependabot[bot] <[email protected]>