fixes zombie infection, and npc zombie infection (#30689)

code/modules/antagonists/zombie/zombie_spells.dm

@@ -161,7 +161,7 @@
 		return // Armor blocks zombies trying to eat your brains!
 
 	// already have the disease, or have contracted it. Good for feedback when being attacked while wearing a biosuit
-	if(target.HasDisease(/datum/disease/zombie) || target.ContractDisease(new /datum/disease/zombie))
+	if(target.HasDisease(/datum/disease/zombie) || target.ContractDisease(new /datum/disease/zombie, SPREAD_BLOOD))
 		playsound(user.loc, 'sound/misc/moist_impact.ogg', 50, TRUE)
 		target.bleed_rate = max(5, target.bleed_rate + 1) // it transfers via blood, you know. It had to get in somehow.
 		for(var/datum/disease/zombie/zomb in target.viruses)

code/modules/awaymissions/mob_spawn.dm

@@ -761,6 +761,7 @@
 /obj/effect/mob_spawn/human/alive/zombie/equip(mob/living/carbon/human/H)
 	ADD_TRAIT(H, TRAIT_NPC_ZOMBIE, ROUNDSTART_TRAIT)
 	H.ForceContractDisease(new /datum/disease/zombie)
+	H.zone_selected = BODY_ZONE_CHEST
 	for(var/datum/disease/zombie/zomb in H.viruses)
 		zomb.stage = 8
 

code/modules/mob/living/carbon/human/species/_species.dm

@@ -1174,7 +1174,7 @@ It'll return null if the organ doesn't correspond, so include null checks when u
 		if(!HAS_TRAIT(user, TRAIT_NON_INFECTIOUS_ZOMBIE))
 			if(!target.HasDisease(/datum/disease/zombie))
 				var/datum/disease/zombie/zomb = new /datum/disease/zombie
-				target.ContractDisease(zomb)
+				target.ContractDisease(zomb, SPREAD_BLOOD)
 
 			for(var/datum/disease/zombie/zomb in target.viruses)
 				zomb.stage = max(5, zomb.stage)