The "precondition" option only works if you schedule a departure time. You can't turn off preconditioning (as far as I know) if you're using departure time. You can only set it to precondition every day vs only weekdays.
If you use the "Start charging at" setting instead departure time, it will NOT precondition the cabin while charging. I have my charging start everyday at 7PM (10PM during the summer to help with the peak load), there's no cabin preconditioning that happens because it has no idea when I'm going to drive the car.