Diseases will now cure if species is changed (#31495)

* Diseases will now cure if species is changed

* Update _disease.dm

* Update _disease.dm

* Update species.dm

code/datums/diseases/_disease.dm

@@ -98,10 +98,10 @@
 					V = Temp
 
 
-/datum/disease/proc/cure()
+/datum/disease/proc/cure(add_resistance = TRUE)
 	if(affected_mob)
 		if(disease_flags & CAN_RESIST)
-			if(!(type in affected_mob.resistances))
+			if(add_resistance && !(type in affected_mob.resistances))
 				affected_mob.resistances += type
 		remove_virus()
 	qdel(src)

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

@@ -257,6 +257,11 @@
 				C.dropItemToGround(I)
 			else	//Entries in the list should only ever be items or null, so if it's not an item, we can assume it's an empty hand
 				C.put_in_hands(new mutanthands())
+	
+	if(VIRUSIMMUNE in species_traits)
+		for(var/datum/disease/A in C.viruses)
+			A.cure(FALSE)
+		
 
 /datum/species/proc/on_species_loss(mob/living/carbon/C)
 	if(C.dna.species.exotic_bloodtype)