feat: Add get_current_conversation to GroupChatManager for agent-specific history

[manishrawal95]

This PR introduces a new method, get_current_conversation, to the GroupChatManager to allow for the retrieval of an agent's specific message history from a group chat.

Problem:
Currently, there is no direct way to get the message history for a single agent participating in a group chat. This makes it difficult to build observability and profiling tools that need to analyze an individual agent's behavior and state, which is a core requirement for projects like my agent-profiler and agent-cost-tracker.

Solution:

• Added get_current_conversation(agent_name: str) to GroupChatManager in autogen/agentchat/groupchat.py.
• The method returns the _messages list for the specified agent.
• Included a unit test to ensure the method functions correctly.

This enhancement makes AutoGen more extensible for developers building monitoring and evaluation tools on top of the framework.

[manishrawal95]

@microsoft-github-policy-service agree