Update Qt AI Assistant to version 0.9.0 (#13)

Updates the Qt AI Assistant plugin registry with the latest version
(0.9.0).

## Checklist

- [x] I have run `npm run all` to validate my changes
- [x] I have made sure my commits are
[signed](https://docs.github.com/en/authentication/managing-commit-signature-verification/signing-commits)
- [ ] I have added an entry for new Extensions in
[CODEOWNERS](/CODEOWNERS)

Author: Maddimax