This refactor the lightprobes sample so that we always query
the spherical probe and the volume probe.
Then, given the BSDF type, we reconstruct the incoming radiance
differently depending on the ray probability blending between
the spherical and volume probe depending on ray probability.
Moreover, we implement cubemap normalization using
volume probe spherical harmonic data at spherical probe
position and at the shading point position.
Pull Request: https://projects.blender.org/blender/blender/pulls/113301
5e43bf3483