In case if some element (not another aggregate) was aggregated by IfcProject directly, importing IFC was resulting in error below since the project's collection was never added to `self.collections`.
Traceback:
```
File "\scripts\addons\blenderbim\bim\module\project\operator.py", line 732, in execute
ifc_importer.execute()
File "\scripts\addons\blenderbim\bim\import_ifc.py", line 292, in execute
self.place_objects_in_collections()
File "\scripts\addons\blenderbim\bim\import_ifc.py", line 1668, in place_objects_in_collections
self.place_object_in_collection(self.file.by_id(ifc_definition_id), obj)
File "\scripts\addons\blenderbim\bim\import_ifc.py", line 1672, in place_object_in_collection
self.place_object_in_decomposition_collection(element, obj)
File "\scripts\addons\blenderbim\bim\import_ifc.py", line 1689, in place_object_in_decomposition_collection
return self.collections[aggregate.GlobalId].objects.link(obj)
KeyError: '2bKVb8E7L6e89EQYJUk8BM'
```
Noticed the issue adding IfcFurnitureType in IFC2x3
```
Traceback (most recent call last):
File "\Blender\4.0\scripts\addons\blenderbim\bim\module\model\workspace.py", line 71, in draw_settings
BimToolUI.draw(context, layout, ifc_element_type="all")
File "\Blender\4.0\scripts\addons\blenderbim\bim\module\model\workspace.py", line 230, in draw
AuthoringData.load(ifc_element_type)
File "\Blender\4.0\scripts\addons\blenderbim\bim\module\model\data.py", line 56, in load
cls.data["predefined_type"] = cls.predefined_type()
File "\Blender\4.0\scripts\addons\blenderbim\bim\module\model\data.py", line 258, in predefined_type
predefined_type = relating_type.PredefinedType
File "\Blender\4.0\scripts\addons\blenderbim\libs\site\packages\ifcopenshell\entity_instance.py", line 191, in __getattr__
raise AttributeError(
AttributeError: entity instance of type 'IFC2X3.IfcFurnitureType' has no attribute 'PredefinedType'
```
It was providing project units to `geometry.add_slab_representation` resulting and then they were converted to project units once again during `geometry.add_slab_representation`.
data.py doesn't update on every undo, so passed blender objects got invalidated on undo resulting in errors. changed blender objects to blender object names
Andrej730