Overcharge - switch how skillchecks work leaving a gen

Currently you can tap a gen that has overcharge applied to it and still hit the skillcheck while running away from it, which doesn't happen with regular skillchecks.

If this were switched around, players repairing a gen wouldn't get screwed over just by repositioning themselves to make room for another survivor and getting a badly timed skillcheck.

Overcharge would also require you to stay on the gen until after getting the skillcheck to not explode it, giving it a more interesting use as an anti-gentapping perk instead of just being an anti-noob perk.