Python/.NET: Consider obsoleting parts of the Agent abstraction

[markwallace-microsoft]

Can we obsolete the channel support?

[crickman]

@markwallace-microsoft

We'll want to do that as part of obsoleting AgentChat and AgentGroupChat. Its all one feature.

Currenttly they are marked as experimental (not graduated).

I think we may want to take a moment to consider our strategy here: how much overlap between continuing to support the AgentGroupChat vs forcing migration to the new orchestration patterns.

We really haven't had any cycles to recieve customer feedback and stabilize the new agent orchestration and we probably want to be very considerate of customers that have invested in the original group-chat and what might be reasonable for their migration timeline.

@alliscode / @sphenry - Any thoughts here in terms of how we want to approach this.

Note: Aggregator agent is also part of this obsoletion bundle as well as the core group-chat strategies. Also, this strategy should apply to both .NET and Python.

[crickman]

Just talked with @shawncal and we may want to consider a 30 day window before deprecating AgentGroupChat and its associated features (such as AgentChannel. This should also include direct messaging (blog / office hours) to customers on when this deprecation will occur,.

I think we want to avoid surprising customers that upgrade SK version and then get a build error on their existing app/service.