Fixes the revblight virus setting it's mob reference to a colour (#20486)

* Fixes the revblight virus setting it's mob reference to a colour

* Refactor revblight cure step

Replaces a spawn with a world time cooldown since we are already processing disease datums in the disease subsystem

* Refactor revblight cure step again

This time to use a timer, also define the color vars properly

* Adjust timing to match previous code

code/game/gamemodes/miniantags/revenant/revenant_blight.dm

@@ -14,9 +14,11 @@
 	severity = BIOHAZARD
 	var/stagedamage = 0 //Highest stage reached.
 	var/finalstage = 0 //Because we're spawning off the cure in the final stage, we need to check if we've done the final stage's effects.
+	var/old_color = ""
 
 /datum/disease/revblight/cure()
 	if(affected_mob)
+		affected_mob.color = old_color
 		affected_mob << "<span class='notice'>You feel better.</span>"
 		if(affected_mob.dna && affected_mob.dna.species)
 			affected_mob.dna.species.handle_mutant_bodyparts(affected_mob)
@@ -58,11 +60,8 @@
 					affected_mob.dna.species.handle_mutant_bodyparts(affected_mob,"#1d2953")
 					affected_mob.dna.species.handle_hair(affected_mob,"#1d2953")
 					affected_mob.visible_message("<span class='warning'>[affected_mob] looks terrifyingly gaunt...</span>", "<span class='revennotice'>You suddenly feel like your skin is <i>wrong</i>...</span>")
-					var/old_color = affected_mob.color
+					old_color = affected_mob.color
 					affected_mob.color = "#1d2953"
-					spawn(100)
-						if(affected_mob)
-							affected_mob = old_color
-						cure()
+					addtimer(src, "cure", 100, FALSE)
 		else
-			return
+			return