Ability to add MessageTransforms to the GroupChat's Select Speaker nested chat (speaker_selection_method='auto')

[marklysze]

This provides the ability to add MessageTransforms to the nested select speaker chat that occurs in a GroupChat when the speaker selection method is 'auto'. The MessageTransforms apply only to the messages within that nested select speaker chat (and not to the broader GroupChat chat).

The GroupChat constructor has a new, optional, parameter called select_speaker_auto_message_transforms that takes in a MessageTransforms object, or None.

Within GroupChat, the provided MessageTransforms object will be assigned to self._auto_message_transforms and used within _auto_select_speaker and a_auto_select_speaker.

The nested select speaker chat has two agents, checking_agent and speaker_selection_agent and the MessageTransforms are added to the speaker_selection_agent as that is the agent that utilises the LLM.

Why are these changes needed?

These changes enable greater control and flexibility of messages for speaker selection. Particularly useful for non-OpenAI models with limited context / reasoning ability.

Related issue number

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• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://microsoft.github.io/autogen/docs/Contribute#documentation to build and test documentation locally.
• I've added tests (if relevant) corresponding to the changes introduced in this PR.
• I've made sure all auto checks have passed.

(2719)

[marklysze]

@marklysze fix the code formating issue? Let me know if you need help!

Okie dokie, should be right to go!

[marklysze]

Just a note - sorry, I accidentally had a local testing file in the commit. I've deleted it.