Mesh export does not work in Blender 4.1 onward

Blender v. 4.1 removed the create_normals_split function from the Python API. Because of this, attempting to export a mesh object now throws an exception, causing no file to be generated.

Reverting to version 4.0 or earlier fixes the issue, but that is not an ideal solution. The scripting should be updated to function with the new API.

Start by locating the Blender Python exporter code that calls create_normals_split, then reproduce the mesh export failure with Blender 4.1 or newer. Update the scripting for the new API and verify that exporting a mesh completes without an exception and generates the expected file.

Written by the indexing model from the issue text.