Fix for 4594f596c2

Traceback:
```
Error: Python: Traceback (most recent call last):
  File "\bonsai\bim\module\project\operator.py", line 127, in execute
    self._execute(context)
  File "\bonsai\bim\module\project\operator.py", line 143, in _execute
    core.create_project(
  File "\bonsai\core\project.py", line 108, in create_project
    project.append_all_types_from_template(template)
  File "\bonsai\tool\project.py", line 55, in append_all_types_from_template
    bpy.ops.bim.select_library_file(filepath=filepath.__str__())
  File "\Blender\4.4\scripts\modules\bpy\ops.py", line 109, in __call__
    ret = _op_call(self.idname_py(), kw)
          ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
TypeError: Converting py args to operator properties:: keyword "filepath" unrecognized
```

src/bonsai/bonsai/bim/ui.py

@@ -39,8 +39,10 @@ from typing import Optional, TYPE_CHECKING
 
 
 class IFCFileSelector:
-    filepath: str
-    use_relative_path: bool
+    # Avoid overriding blender prop annotations at runtime.
+    if TYPE_CHECKING:
+        filepath: str
+        use_relative_path: bool
 
     def is_existing_ifc_file(self, filepath: Optional[str] = None) -> bool:
         """Check if file path exists and if it's an IFC file.