Spring-ai #1676 Fix open api response deserialization

Added properties to OpenAi response according api reference

https://platform.openai.com/docs/api-reference/making-requests

Comment From: markpollack

Thanks! I review the response fields in https://platform.openai.com/docs/api-reference/chat/object and there was also one relating to audio. I updated the OpenAIUsage object to be able to return these fields and added some unit tests for sanity checking. Good idea with @JsonIgnoreProperties(ignoreUnknown = true) - prob need to review using that more frequently to guard against changes that can happen unexpectedly with model apis.

merged in cd886437eb1a6a5ec9bc7b7bf367a94a098c1dcc