PR: TreadLengthAtInnerSide & WalkingLineOffset attributes export with wrong values

### Problem Description

#### When exporting winding or spiral stairs:
The attribute ```TreadLengthAtInnerSide``` both in ```Pset_StairCommon``` as well as ```Pset_StairFlightCommon``` gets exported with a wrong value, in that it just seems to replicate the value of ```TreadLength```.

#### When exporting *any* stairs:
```WalkingLineOffset``` gets a wrong value (1.64 x run width). For winding or spiral stairs there is no relationship with the STAIRS_WINDERPATTERN_STAIR_PATH_OFFSET parameter of the stair run.

#### Expectation
While this is happening it would be better not to export those attributes at all.

Tested for IFC4 RV Arch.

### Revit Version

2023.1.x

### IFC for Revit Addon Version

23.2.5

### Windows Version

10 22H2

Start by locating the IFC export logic for stair and stair-flight properties, especially where Pset_StairCommon and Pset_StairFlightCommon populate TreadLengthAtInnerSide and WalkingLineOffset. Compare those values with the reported Revit stair parameters and the expected IFC4 output; done means the incorrect attributes are not exported until valid values can be provided.

Written by the indexing model from the issue text.