When a mesh light is shadow-linked to something with a specific
shader network it was possible that the emission_sd_storage was
not bit enough for sampling.
The shade_dedicate_light kernel only evaluates emission of either
light or mesh emitter and then resumes the regular path tracer.
There is no need to store closures.
This change makes it so a smaller storage is used, and also
passes flag to the shader evaluation function indicating that
closures are not to be stored.
Pull Request: https://projects.blender.org/blender/blender/pulls/116907