fix: don't un-XL clothes you're wearing if you're Huge

[chaosvolt]

Purpose of change

This adds a bit of sanity-checking for a problem found out while testing the implementation of #3967

Describe the solution

In iuse_actor.cpp, updated sew_advanced_actor::use so that the if/else statements that check whether you can proceed with installing or removing a clothing_mod also check whether the mod would result in the item becoming unwearable, and if so preventing you from doing so if you're also currently wearing the offending item.

Also had to move the definition of t_lower a bit so that the destroy part of the if/else block can also use it.

Describe alternatives you've considered

Adding support for resizing for smol characters too. I think I'd want to wait on that one and add it along with some more properties and fixes, like support for making a gunmod not need materials to apply, volume/weight multiplier, etc.

Testing

1. Compiled and load-tested.
2. Spawned in a tailor's kit and a bunch of rags.
3. Applied and removed the resize mod to an item while a normal human bean, things went as normal.
4. Enlarge-ified myself and modded my shirt to be XL, works as normal and can wear it.
5. Try to revert the resize while wearing it, it won't let me.
6. Wield the shirt, it now allows me to remove the resize mod.
7. Checked affected file for astyle.

Additional context

Checklist

[chaosvolt]

So I'm testing this and it seems super-smol characters currently no longer actually have gear restrictions for oversized gear, just encumbrance penalties, so resizing for smol characters seems to not be as vital as I thought it'd be.

[scarf005]

Attempting to un-XLing worn clothes

Attempting to un-XLing not worn clothes

had save compatibility issue (#3988), but it's unrelated to the PR.
LGTM.