Fix typo in teams.ipynb documentation

[a4archit]

Why are these changes needed?

I fix a typo mistake in the documentation, in the article -> https://microsoft.github.io/autogen/stable//user-guide/agentchat-user-guide/tutorial/teams.html#running-a-team

Related issue number

There was no issue raised i just find a repo mistake and improve it.

Checks

• I've included any doc changes needed for https://microsoft.github.io/autogen/. See https://github.com/microsoft/autogen/blob/main/CONTRIBUTING.md 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.