On the B777 all that the crew crew are allowed to do is switch the lights to the night setting, this will leave a certain amount of lighting on within the cabin, there is no choice and it is whatever has been set by the engineers directed by safety services. If there were complaints or the crew thought the lighting was brighter than normal they can log this in the Cabin Techical log book.
There is an off setting which is not to be used as the lighting in First is on a different system to the rest of the aircraft and if there was a decompression when all the cabin lights come on full having the First lights set to off the cabin would remain in darkness.