A few files included in reports contained normals that were not normalized.
In order to contain consistent normals around smooth corner fans, sharp
edges are added when neighboring corner normals aren't close enough.
Non-unit-vector normals also triggered this check.
Blender used to do this implicitly when the derived `MeshLoop.normal`
value was set. That API has been changed already, and it's clearer if the
addon provides normalized normals, so this PR adds a normalization
step to the FBX importer.
Pull Request: https://projects.blender.org/blender/blender/pulls/124261
4e6a962b2b