Allow sending an option without updating the messages

[HunderlineK]

Is your feature request related to a problem? Please describe.
I'd want to be able to prompt a chat history with a message without having the interaction stored in the messages

Describe the solution you'd like

• Add an option that allows sending a message to a chat without storing it chat.send(..., { updateMessages: false})
• In addition to a boolean, the argument could also be a function that accepts the response as an input e.g. an evaluator , in which case the messages are updated only if the function returns true, which could be useful for implementing guards

Describe alternatives you've considered

• We can retrieve the chat messages and manually delete the unwanted interactions, but it's clunky and need careful consideration of race conditions to prevent deleting incorrect messages.
• We can also create a separate evaluator agent that retrieves all the messages from the chat agent and then analysis them separately, but it can lead into duplication of the agent, system instructions, etc. and the chat history has to be copied around and discarded unnecessarily.

Additional context
For a use case e.g. assume a customer is chatting with a support AI agent and there is a monitoring system that periodically queries the chat history to evaluate if the customer is happy or not, and we do not want the evaluator's query and the AI agent's response to be stored in the history of the messages.