Agent name termination

[thainduy]

Why are these changes needed?

Introduces the AgentNameTermination class, which is a termination condition for conversations based on last agent name

Related issue number

Checks

• [ ] 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.

[thainduy]

@microsoft-github-policy-service agree

[thainduy]

Let's move this into autogen-agentchat, there is no external dependency.

moved to autogen-agentchat, pls check again