[TME] Kart color override crashes on karts not supporting custom colors

[Nomagno]

This happens when the "Make kart color depend on tyre" option is enabled, and you attempt to start a race with a kart that doesn't have any configured color-changeable materials (e.g. black hole). The fix should be to detect this at run-time and only dynamically change the color of the karts that support it.

[Nomagno]

Upon further investigation, it seems this is actually not explicitly supported by any boolean method, and karts with no color support don't crash the game because of some kind of implicit guarantee of the color code that I haven't quite figured out yet