CI started failing: `The model `chatgpt-4o-latest` does not exist or you do not have access to it.`

[amotl]

Problem

The software tests started failing on CI:

NotFoundError: Error code: 404 - {'error': {'message': 'The model `chatgpt-4o-latest` does not exist or you do not have access to it.', 'type': 'invalid_request_error', 'param': None, 'code': 'model_not_found'}}

-- https://github.com/crate/langchain-cratedb/actions/runs/22544017083/job/65303410431?pr=92

[amotl]

While looking into this, we also discovered that the nightly scheduled test run succeeds without actually validating anything.