Sketcher: B-Spline by knots - weird snapping to imported external geometries

### Is there an existing issue for this?

- [X] I have searched the existing issues

### Problem description

Trying to make a B-Spline by knots attached to points imported from an external geometry results in weird snapping to points. Looks to me like something like an indexing error.

### Full version info

```shell
OS: Ubuntu 22.04.5 LTS (KDE/plasma)
Word size of FreeCAD: 64-bit
Version: 1.0.0RC1.38642 (Git) AppImage
Build type: Release
Branch: (HEAD detached at 1.0rc1)
Hash: 60a251354e203bdb924e2190fb9f5e18b48d7362
Python 3.11.9, Qt 5.15.13, Coin 4.0.2, Vtk 9.2.6, OCC 7.7.2
Locale: German/Germany (de_DE)
Installed mods:
* Estimate 0.1.2
* AirPlaneDesign 0.4.0
* Curves 0.6.40
* Manipulator 1.5.7
* CurvedShapes 1.0.9
* OpenDark 2024.3.13
```

### Subproject(s) affected?

None

### Anything else?

[Weird_b_Spline_by_knots_in_Sk_referencing.zip](https://github.com/user-attachments/files/17096370/Weird_b_Spline_by_knots_in_Sk_referencing.zip)

### Code of Conduct

- [X] I agree to follow this project's Code of Conduct