MagenticOne Team uses local code execution by default

[husseinmozannar]

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Issue body

The MagenticOne team uses local code execution by default.

DockerCodeExecution should be default and we should stop users from trying to run it if they don't have docker installed.

https://github.com/microsoft/autogen/blob/main/python/packages/autogen-ext/src/autogen_ext/teams/magentic_one.py

[afourney]

Yes, this has been throwing a DeprecationWarning for a while now. We should be ok to finally remove that behavior in the next release.