Debug pie chart doesn't scale with GUI scale & appears tiny on high resolution monitors

The bug

When you change the GUI scale in the settings, the pie chart on the debug screen doesn't scale with the rest of the UI, making it very difficult to see on higher-resolution monitors.

How to reproduce

1. Press Shift+F3 to enable pie chart
2. Pause the game, go to Options->Video Settings
3. Cycle GUI scale to anything above "small"
4. Resume the game

Even if I disable and re-enable the pie chart with Shift+F3, the issue is not resolved. The screenshots show how difficult it is to read the pie chart on higher resolutions monitors.