AzureOpenAiChatPromptDriver and structured_output

[vachillo]

getting the following error when trying to use EvalEngine with AzureOpenAiDefaultsConfig:

400 - {'error': {'code': 'BadRequest, 'message': 'response_format value as json_schema is enabled only for api versions 2024-08-01-preview and later'}}

we should probably bump the default api_version for those drivers.

[collindutter]

Tracking that here

[collindutter]

#1662