Due to the refactoring of the overlay engine the draw caches were changed. The sphere batch used to have positions and normals. After the refactoring it didn't had the normals anymore. The normals are needed for shading. As they were not there the look dev spheres were rendered black. This change add the `nor` attribute to `DRW_cache_sphere_get` batch. Reviewed By: fclem Differential Revision: https://developer.blender.org/D6393