HI Benjamin;
PowerServer Mobile does not support the flashlight functionality at this time. However, PS Mobile's AWS does provide Cordova plug-in access. AWS does map the popular Cordova plugins for you - but, AFAIK - not this particular one. You can install a Cordova plug-in yourself though and then wtite some jScript to acces it. There are quite a few Cordova plug-ins that can control the flashlight, for example: Click here.
This would make a great feature enhancement. Please open a support ticket for this and request it as a new requirement. The Support Team will then add this to Engineering's enhancement list.
Regards ... Chris
Regards
Benjamin