Mac already uses diverse font sizes (for instance, smaller fonts for
radio button groups), and the anti-aliasing is a lot better. The
other platforms need a more limited range of sizes.
Fixes https://gitlab.com/kicad/code/kicad/issues/8608
When the window is not active, the status bar uses disabled text,
so the message panel sticks out because it is then using a different
text color. This is most noticable in dark mode.