ENH: Export Material Description to IfcMaterial.Description in IFC4

### Enhancement Description

When you export a material the description is not included in the IFC file.
Only when you check to include the material properties in the export, the description is included as a separate property.

In [IFC4](https://standards.buildingsmart.org/IFC/RELEASE/IFC4_3/HTML/lexical/IfcMaterial.htm), it is possible to include the description of a material as an attribute, as is already done with the "Name" and "Class" parameters of Revit.

It would be better to include the "Description" as an attribute of IfcMaterial by default instead of with the material properties.

### Revit Version

2024.0.x

### IFC for Revit Addon Version

24.x.x

### Windows Version

11 22H2

No source files or tests are named. Start by tracing the IFC4 material export and the existing mapping of Revit’s Name and Class parameters to IfcMaterial, then compare the generated IFC with the IFC4 IfcMaterial definition. Done means Description is emitted as the IfcMaterial attribute by default rather than only as a separate material property.

Written by the indexing model from the issue text.