PR: Revit 2026 IFC structural export: predefined types not exported (ifcbeam and ifc column)

### Problem Description

If ifc predefined type is used with structural beams and columns those elements not exported. Unfortunately there is no option to revert back if predefined type is already set.

This behaviour started with latest revit update and seems to affect all IFC from 2x3 to IFC 4 (tried multiple versions and settings)

### Revit Version

2026.4.x

### IFC for Revit Addon Version

26.4.1

### Windows Version

11 25H2

Start by reproducing the export in Revit 2026.4.x with IFC for Revit 26.4.1, using structural beams and columns with predefined types across the reported IFC versions and settings. Compare the resulting IFC files with exports where predefined types are not set; done means both element types are exported correctly with their predefined types.

Written by the indexing model from the issue text.