Python: semantic_kernel.connectors.ai.open_ai.OpenAIChatCompletion is missing endpoint property

[madsbolaris]

In .NET, when constructing an OpenAIChatCompletion, you can provide an optional endpoint property to connect to local models and other services that use the OpenAI API specification.

[alliscode]

@TaoChenOSU I believe this can be closed with the work you are doing to support local models on python. Can you verify?

[TaoChenOSU]

Yes, there is not an endpoint argument to the connector, but you can provide a custom client.

I will link the PR to this issue.