Audits wash/cleaning signals + refactors wash() to ensure no needless mob updates occur (#91259)

## About The Pull Request

This has the potential to create a lot of needless mob updates which is
not great. Now should only update a mob's clothing if it was actually
washed.

This PR

1) ensures that all wash() procs return a bitflag.
2) ensures that `wash()` proccalls which result in expensive operations
like icon updates only do so when it is necessary

## Why It's Good For The Game

Updating mob sprites is expensive, and doing it when nothing has been
changed is bad.

## Changelog

Nothing really player facing

code/game/objects/effects/decals/cleanable.dm

@@ -61,9 +61,9 @@
 
 /obj/effect/decal/cleanable/wash(clean_types)
 	. = ..()
-	if (. || (clean_types & clean_type))
+	if (. || clean_types & clean_type)
 		qdel(src)
-		return TRUE
+		. |= COMPONENT_CLEANED|COMPONENT_CLEANED_GAIN_XP
 
 /obj/effect/decal/cleanable/proc/handle_merge_decal(obj/effect/decal/cleanable/merger)
 	if (!reagents && !decal_reagent)