Previously, 4e9e44ad made changes to allow GSpan and GMutableSpan to not
have a type when they are empty. This mirrors the same change in the
conversion from GArray to both span types and when converting to an
actual typed Span<> or MutableSpan<> via typed().
Fixes #125013
Pull Request: https://projects.blender.org/blender/blender/pulls/125018