Complete the versioning and writing changes from these commits:
- f9b627d29c
- f2bcd73bd2
- c5ba8bd7c2
4.5 has the forward compatibility handling to support reading files
written by 5.0. This removes the conversion when writing files
and removes the lookup of ".uv_seam" as a fallback for "uv_seam".
Pull Request: https://projects.blender.org/blender/blender/pulls/139841