Dunno in Brazil as a whole but at least in my city, school uniforms are default. They’re simply taken for granted, not a “conservative vs. liberal” matter. Each school picks its own, but it usually boils down to a shirt, baggy pants, and a jacket (most schools cut you some slack on really cold days to swap it with a warmer one).
No, but simply looking for something and then remembering that it doesn’t exist makes me feel stupid.