Fix in-game customization

[furran]

Summary

Bugfixes "Fix in-game customization when using hair trimmer, hand mirror, etc"

Purpose of change

Currently if the player uses a hand mirror, standing mirror or hair trimmer and picks a in-game customization option that implements variants, the variant will be randomized.

This fix makes it so the player is prompted to pick a variant for the selected trait instead (if it has them).

Closes #69944

Describe the solution

Altered the customize appearance function so you first select the trait and then you can select the variant for that trait (if it has variants).

Describe alternatives you've considered

Undoing variants for all cosmetic mutations that use them, but that felt like going backwards.

Testing

Get in game, spawn a hand mirror, select eye color and pick a color.

Additional context

This PR was split from #70017

[Standing-Storm]

If it's not too much of a hassle, is there a possibility to link this customization into an effect that could be called by EoC? When I checked, the existing barber_hair and barber_beard only work in dialogue with an NPC and there's no way to customize skin or eye color through EoC at all.

[furran]

@Standing-Storm hmm I think it would be out of scope of this PR since I am just making it so you have to pick a variant if you select a trait that has them, as opposed to have it randomized in the customization screen. Also, I haven't messed with EoCs at all yet. Really out of my depth there atm