icon_theme needs a similar setup for changing between light/dark mode like theme does.

[tkgalk]

Discussed in #24370

^{Originally posted by Amparose February 6, 2025}
Currently an icon theme is set with "icon_theme": "Material Icon Theme",.

I would like it to work like themes:

"icon_theme": {
    "mode": "system",
    "light": "Zed (Default)",
    "dark": "Material Icon Theme"
  },