Visible seam on smoothed sphere and cylinder shapes

[MythTitans]

Godot version

3.4.2-stable, v4.0.dev

System information

Windows 11, Vulkan

Issue description

When the Smooth Faces option is enabled on CSG sphere and cylinder shapes, they produce a visible seam at the junction of their first and last radial segment.

Steps to reproduce

Create a CSGSphere3D or CSGCylinder3D object and the seam should be immediately visible. Adding an OmniLight3D close to it can make the seam even more visible.

Minimal reproduction project

No response

[Calinou]

Related to #49800.

[MythTitans]

The same problem is present on torus, can be fixed in PR #59002.