This is a Reed- or hall-sensor engaged by the magnet in cover which holds the kickstand. It's an electronic component that needs a tiny bit more than just soldering two wires to it, to replace it with a mechanical switch inside a slot-in uSD holder. You'll at least need a cmos gate plus some ESD protection measures to avoid frying the gate and/or the CPU itself when something odd happens to your slot-in uSD-holder, like you discharging your wool pullover to the slot.

/j