FontStyler.Set() disposes SKTypeface prematurely

**Issue:** (Describe the bug here)

**ScottPlot Version:** (5.0.55)

```cs
Fonts.AddFontFile(fontName, filePath);
WpfPlot1.Plot.Font.Set(fontName);
```

![Image](https://github.com/user-attachments/assets/50c660b0-0cea-4353-baa6-81f273cadccf)

My guess is that it is causing SKTypeface to become invalid in the cache