Right, like Infletcher said. Something like this one:
These often have three pins and can be wired either normally open or normally closed. If you look closely you can see the pins on this one are labeled (L-R): C (common / hot), NO (normally open) and NC (normally closed).
Wire it so it's normally closed. The circuit will be open when the roller is pressed against the brake arm and when you press on the pedal the arm will move away from the roller and close the circuit, energizing the brake light circuit.
https://www.digikey.ca/en/products/d...SS-5GL2D/17243