enable the ability to swap the messages of the code preview

[cobycloud]

we want to use the conversation.add_messages() interface to add a list of Messages
this list of messages must correspond to the conversation.history in the chat

[cobycloud]

we want to use the conversation.add_messages() interface to add a list of Messages to the Code preview.
this list of messages must correspond to the conversation.history in the chat.

example:

user: "hi"
bot: "hello"

code preview:

messages = [HumanMessage(content="Hi"), AgentMessage(content="hello")]
conversation.add_messages(messages)