Can confirm that there is a working light in the glovebox on 2016 GTIs. The cable is pretty short to be fair so if you had work done in that area there is high chance it's tucked in somewhere inside the dash and the guy that worked on your car has not bothered to connect it back. On my previous 2014 GTI the cable was even shorter, I could barely take it out to change the bulb with a LED bulb.