Yes, of course they’re using your code to train their models. That use is in their terms and their licensing.

It’s irrelevant to your point but this is absolutely not true. As far as I know they don’t have legal basis to violate software licenses of new projects added to github, but even if I’m mistaken on that an enormous number of projects were on github when microsoft purchased it, and almost all of them were at minimum licensed so that code usage required attribution. Microsoft has been very aware that no person or organization behind a project hosted on github has the financial resources to take them to court.