More accurate checking in layering conflicts

[bombasticSlacks]

Summary

Bugfixes "More accurate checking in armor layering conflicts"

Purpose of change

fixes #54871

Describe the solution

The really low level layer conflict code was using a simple convenience function, originally used for if items should display a UI element, to test if it should do sublimb testing on the items in question or just assume they conflict. This was dumb and wrong of me.

Some test needs to be there since some limbs don't have sublocations.

So I removed the incorrect it.has_sublocations() test and instead just test if the bodypart has sublimbs a much simpler solution which is also correct.

Describe alternatives you've considered

Testing

Try the heavy load bearing vest and a duffel bag.

Heavy Ballistic Vest with an attached pouch and a shoulder strapped rifle is the test with just about the most edge case opportunity and it works.

Additional context

I need to spend some time at some point writing a bunch of test items and tests for this.