Update import in the Tutorial Files

[bmoussaud]

Why are these changes needed?

I followed the Python Tutorial and found several error in the import. I fixed them.

Related issue number

Checks

N/A

• 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.

[ekzhu]

Thanks @bmoussaud mostly this is caused by you are viewing dev version of the agentchat documentation. The package will be updated once we make a new dev release this week.

[jackgerrits]

I believe this is resolved with the new dev release and version selection on the website. Please feel free to reopen if it's still an issue.