logprobs support for ChatOpenAI

[jfayad]

I noticed that logprobs are not supported for ChatOpenAI.

I also noticed DeepSeek does support them.

We could use the same approach to include logprobs in the returned Message metadata

[jfayad]

I pushed a fix to support top_logprobs with the Responses API

I can see it being sent to the API but looks like my API provider (Scaleway) doesn't correctly support it, can anyone with access to OpenAI official API confirm this works well and return the logprobs values per token (similar to how it behaves on the chat/completions API) ?