See #105317
In 46cf093270, face maps were just converted to an integer
attribute. While the internal data remains the same that way, we lose
the names and some convenient methods of interaction. This commit
additionally converts each face map to a separate boolean attribute
using the old name. This does require that no attributes were using that
name already.
Each boolean attribute can be thought of as a selection, accessible in
geometry nodes and properly interpolated by mesh processing
algorithms. The selections no longer have to be unique, meaning
one face can be part of multiple selections.
Pull Request: https://projects.blender.org/blender/blender/pulls/113769
820f0c24c4