feat(jans-auth-server): update first party native authn implementation ( in backwards compatibilty way)

### Description

Update first party native authn implementation.
It must be updated in backwards compatibilty way because it is already in use.

https://datatracker.ietf.org/doc/draft-parecki-oauth-first-party-apps/02/

### Test cases and code coverage

- [x] Write unit test to cover added/changed code
- [x] Update integration tests to cover added/changed code
- [x] documentation

