We're back to DogCow's point. This isn't a first order consideration. You lose far more in heat due to opening the door.
Do you want regulations banning french door refrigerators due to efficiency? If you really care about efficiency, get a chest refrigerator. The bulb's heat output isn't salient, but the air temp dump due to opening the door certainly is. A chest refrigerator avoids that.
However, mandating LEDs in regular fridges is like mandating low rolling resistance tires for H2 Hummers. LRR tires make sense on a Prius, but they are a pointless "improvement" on an H2.