ba85f96f7a
Part of incoming refactors in interface layout C++ code, this enables forward declaring this enum type outside of `layout_interface.cc`. The enum is renamed as `ItemType` and moved to the `blender::ui` namespace. `uiItemType` is preserved as a shorthand for `blender::ui::ItemType`. No user visible changes expected, layout introspection will still print item types using property enum identifier format. Pull Request: https://projects.blender.org/blender/blender/pulls/136740