It's a cloudy day in Atlanta, Millie Bobby Brown is bleeding from the nose, and an automobile has been violently flipped over. "There's a car," Brown says, psyching herself up between takes, "and I'm going to move it with my brain." This was the sight I took in when Collider visited the set of Stranger Things season 3. And when I say "set", I mean the Starcourt, an actual down-on-its-luck mall just outside the city that the show's production took over, infused with a healthy dose of neon lights, and transformed into a …