For some reason, the `underwater_caustics` test was failing on Metal
after #140480 even though that test doesn't use the Sky Texture.
After messing with the file for a while, going back to the previous version
and adding the changes back one at a time, I've now arrived at a version
that behaves the same way as the #140480 version without breaking the test.
No idea what is the underlying issue, but we've had problems with the MNEE
kernels before so maybe just a compiler thing.
Pull Request: https://projects.blender.org/blender/blender/pulls/146335