Fix support for Wireframe and parametric nodes by resolving compilation failures surrounding barycentric coordinates. A final missing part of the Metal implementation for barycentric coordinates was missing. Feedback also addressed to move barycentric calculation out of code-gen and into surface_lib. Authored by Apple: Michael Parkin-White This also resolves #103606. Ref #96261 Pull Request: https://projects.blender.org/blender/blender/pulls/105740