I'm going to take a stupid wildass guess on this. Typically Toyota sends +12V to all bulbs and relies on an applied ground to turn them on. In this case it is the door switch. There may be a common +12 going up in the headliner for both dome and cargo lights. You might get lucky and the wiring for the cargo light may splice into the wiring for the dome light and you could cut it. Try pulling down the dome light and see what is up there.

1997 T-100 4X4 Xcab,Warn Hubs
02 Camry LE
2008 Yaris