Legend: rendering text labels resets custom typefaces

https://github.com/ScottPlot/ScottPlot/discussions/3825#discussioncomment-9433290

![image](https://github.com/ScottPlot/ScottPlot/assets/4165489/2958e6e8-2966-46f7-87cf-8f17040e8591)
