I am on a personal gmail so I can't test this myself. However, I suspect it might not prevent it. The feature you linked seems to just allow you restrict domain

I am on a personal gmail so I can't test this myself. However, I suspect it might not prevent it. The feature you linked seems to just allow you restrict domains that projects within your org can be shared with. The issue is not that you're sharing projects with someone else, but that they're sharing projects with you. So in that case, this feature would do nothing to block that as far as I can tell. That is unless they add the ability to block someone outside sharing stuff with you (which I did not see any mention of after a quick skim of the link you posted).