a single led bulb uses about 0.020 Amps per hour. so.. figure that one out. average car battery has what? 400A?
so yeah.. doing the math (figuring its only one bulb) if you were to leave your car untouched for 833.3 days... it'd kill your battery.
but thats with the light on. the little bit thats coming through is probably somewhere around 0.001 amp. just enough to produce a pin point of light.
so.. uh.. no. no worries.