[OpenAI] Investigate the error message POJO that works for both AOAI and OAI

[mssfang]

(1) It is possible that AOAI error message is different between different models. For example, gpt-35-turbo, we could have

{
  message: 'Unrecognized request argument supplied: tools',
  type: 'invalid_request_error',
  param: null,
  code: null
}

gpt35-turbo-instruct, we could have

{
  code: 'OperationNotSupported',
  message: 'The chatCompletion operation does not work with the specified model, gpt-35-turbo-instruct. Please choose different model and try again. You can learn more about which models can be used with each operation here:
https://go.microsoft.com/fwlink/?linkid=2197993
.'
}

And investigate the different between models in OAI.

(2) Need to investigate the different between AOAI and OAI error message's structure