Cycles did not update the "is_enabled" flag on lights when they were synchronized again, which caused all lights disabled by "LightManager::disable_ineffective_light" to be disabled indefinitely. As a result the OptiX kernels were not reloaded with correct features when a change to a light was made. This fixes that by updating the "is_enabled" flag during synchronization.
Differential Revision: https://developer.blender.org/D6141