Changes MMI to use sprite overlays (#35088)

* MMI now uses overlays

* .

code/modules/mob/living/brain/MMI.dm

@@ -2,7 +2,7 @@
 	name = "Man-Machine Interface"
 	desc = "The Warrior's bland acronym, MMI, obscures the true horror of this monstrosity, that nevertheless has become standard-issue on Nanotrasen stations."
 	icon = 'icons/obj/assemblies.dmi'
-	icon_state = "mmi_empty"
+	icon_state = "mmi_off"
 	w_class = WEIGHT_CLASS_NORMAL
 	var/braintype = "Cyborg"
 	var/obj/item/device/radio/radio = null //Let's give it a radio.
@@ -15,21 +15,19 @@
 	var/overrides_aicore_laws = FALSE // Whether the laws on the MMI, if any, override possible pre-existing laws loaded on the AI core.
 
 /obj/item/device/mmi/update_icon()
-	if(brain)
-		if(istype(brain, /obj/item/organ/brain/alien))
-			if(brainmob && brainmob.stat == DEAD)
-				icon_state = "mmi_alien_dead"
-			else
-				icon_state = "mmi_alien"
-			braintype = "Xenoborg" //HISS....Beep.
-		else
-			if(brainmob && brainmob.stat == DEAD)
-				icon_state = "mmi_dead"
-			else
-				icon_state = "mmi_full"
-			braintype = "Cyborg"
+	if(!brain)
+		icon_state = "mmi_off"
+		return
+	if(istype(brain, /obj/item/organ/brain/alien))
+		icon_state = "mmi_brain_alien"
+		braintype = "Xenoborg" //HISS....Beep.
 	else
-		icon_state = "mmi_empty"
+		icon_state = "mmi_brain"
+		braintype = "Cyborg"
+	if(brainmob && brainmob.stat != DEAD)
+		add_overlay("mmi_alive")
+	else
+		add_overlay("mmi_dead")
 
 /obj/item/device/mmi/Initialize()
 	. = ..()