Remove old agent orchestrator work via Arch-Function after plano ships

[salmanap]

Once we ship plano, we will have to versions of the agent orchestration logic and we can only support one going forward. This issue is to track this removal and make sure our config generator fails if we get the old config as agent orchestration will be a breaking change and be supported in plano via our v2 config format.

[zakariyaahaddout5-coder]

Zakariyaa haddout