[Python] Mesh data is duplicated, not cached

[dylanebert]

• When multiple objects have the same mesh, it should only pass the mesh data once, as it worked previously
• Currently, the mesh data is instead duplicated, i.e. adding 100 equivalent spheres will pass 100 different mesh data

[dylanebert]

Mesh caching works correctly if the meshes share the same material, so the issue may be that the material is being factored into the mesh caching, but the same mesh should be able to be used for different materials