This addresses warnings from Clang-Tidy's `readability-else-after-return`
rule in the `source/blender/editors/transform` module.
No functional changes.
Part of T68836
`transform conversions.c` is a file that is getting too big (almost 10,000 lines).
So it's a good idea to split it into smaller files.
differential revision: https://developer.blender.org/D5677
