.NET: Investigate ways to simplify constructing a responses based agent with store=false

[westey-m]

To enable this scenario is quite hard at the moment, since you have to use break glass via the RawRepresentationFactory on ChatOptions, which in turn is on ChatClientAgentOptions.

We should investigate if we can add helpers to make this easier.

AIAgent agent = new OpenAIClient(
    apiKey)
     .GetResponsesClient(model)
     .CreateAIAgent(options: new() { ChatOptions = new() { RawRepresentationFactory = (_) => new CreateResponseOptions() { StoredOutputEnabled = false } } });