PR: Problem with Z coordinate when using "Link IFC"

### Problem Description

I have an issue with the "Link IFC" functionality in Revit 2025-2027. In these versions, the building geometry is positioned higher than it should be, and the levels are created at twice the correct elevation. ("Open IFC" handles the coordinates much better.)

I do not have this issue in Revit 2023/2024. In those versions, the Z coordinate is correctly mapped to the Project Base Point.

Ill send a file to ifc-github-support@autodesk.com so you can reproduce the issue

### Revit Version

2027.0.x

### IFC for Revit Addon Version

27.0.1.1

### Windows Version

11 25H2

Start with the supplied reproduction file and compare "Link IFC" with "Open IFC" in Revit 2025-2027, then contrast the result with Revit 2023/2024. Trace how the Z coordinate is mapped to the Project Base Point; done means geometry and generated levels have the correct elevation in the affected versions.

Written by the indexing model from the issue text.