refactor: remove identity.rs logic from validate_credential_jwt

[Oran-Dan]

Description of change

BLOCKER: discuss whether we should issue OBv3 as jwt_vc_json in the first place.

The validator from identity.rs only allows for VC 1.1 based credentials. We need to issue VC 2.0 based credentials as well.

Links to any relevant issues

How the change has been tested

Old tests still pass, since it's a refactor no new tests are needed.

Definition of Done checklist

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• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes