There was actually just a recall issued on that. Deemed a fire hazard so they have been disabled until a proper fix is developed. Dealer likely did it before delivery if you got it recently. Though yes if you go into the car settings there is a setting there for the brightness. But that setting was also removed via the recall.
https://forums.vwvortex.com/showthre...another-recall
NHTSA RECALL NUMBER
18V467
START DATE
07-24-2018
DESCRIPTION
High humidity in the panoramic sunroof ambient lighting bar LED module (caused by environment or by leaving the sunroof open) could lead to a local short circuit. If this happens, there is a risk of a fire.
REMEDY
Disable the power supply to the panoramic sunroof LED module. In the future, a service action will be implemented to safely reactivate the feature.