fix(bridge/ndcore): toString on null

[Andyyy7666]

Pull Request Description

Please include a general description of the changes made, why they were necessary, and any other general things to note.

Pull Request Checklist:

• [x] Have you followed the guidelines in our Contributing document and Code of Conduct?
• [x] Have you checked to ensure there aren't other open Pull Requests for the same update/change?
• [ ] Have you built and tested NPWD in-game after the relevant change?