Support OAuth2 Scopes for Authentication

[SoulPancake]

Checklist

• I agree to the terms within the OpenFGA Code of Conduct.

Describe the problem you'd like to have solved

Current SDKs only support Auth0's client credentials flow implementation.

Describe the ideal solution

In order to also support standard OAuth2 client credentials flow, the audience parameter should be made optional and another optional scope parameter should be added.

Alternatives and current workarounds

No response

References

No response

Additional context

No response