Makes dust animation look less 2006 (#87435)

## About The Pull Request

This was inspired by an effect I saw on Paradise but I sprited my own


https://github.com/user-attachments/assets/2130053c-a6ea-48e6-8b62-4c08563fd154

(Todo, make the skeleton appearing less jank)

## Why It's Good For The Game

1. Looks less 2006. 
2. The dust sprite will reflect the mob being dusted, since it's
literally just Your Sprite. Your clothes, species, etc.
3. All species and all mob types now animate being dusted - from corgi
to xenos, from borgs to lizards -, and we can even reuse this effect for
items being dusted if we so desire

## Changelog

🆑 Melbert
image: The animation for being dusted now takes into account your
sprite, rather than being a normal nude spaceman
/🆑

code/modules/unit_tests/focus_only_tests.dm

@@ -53,3 +53,6 @@
 
 /// Catches any invalid footstep types set for humans
 /datum/unit_test/focus_only/humanstep_validity
+
+/// Checks icon states generated at runtime are valid
+/datum/unit_test/focus_only/runtime_icon_states