Update call pattern to OpenAi to use new protocol #19
Description
The _openai_api_request method in pynguin/languagemodels/model.py uses the new protocol to interact with OpenAi compatible models (documentation linked here).
The _openai_api_legacy_request method uses the old protocol that was previously used by Codamosa to interact with the OpenAi model. Need to validate that the new method works with the OpenAi model (hosted by OpenAI server) and remove the _openai_api_legacy_request if the new method works successfully.