On a user level this fixes configuration when a spot light is
linked to an object, and a sun light is not linked to anything.
It used to be making non-linked receivers to be very noisy.
This is because the distant light did not update the node's
light linking settings when they are added to the node.
A simple demo file will be added to the tests suit as
light_link_distant_tree.blend.
Pull Request: https://projects.blender.org/blender/blender/pulls/108311
4ca39297ab