Add extra tab for AutoGen on the web

[skzhang1]

Why are these changes needed?

Add an extra tab for AutoGen on the web.

Related issue number

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