Adds a cap to Xenobiology Mobs and Allows Sentient Giant Spider prompts to be disabled (#17316)

Co-authored-by: dearmochi <1496804+dearmochi@users.noreply.github.com>

code/modules/mob/living/simple_animal/hostile/giant_spider.dm

@@ -56,12 +56,6 @@
 		for(var/obj/structure/spider/S in range(1, get_turf(src)))
 			return S
 
-/mob/living/simple_animal/hostile/poison/giant_spider/death(gibbed)
-	. = ..()
-	if(!.)
-		return FALSE
-	SSmobs.giant_spiders--
-
 //nursemaids - these create webs and eggs
 /mob/living/simple_animal/hostile/poison/giant_spider/nurse
 	desc = "Furry and black, it makes you shudder to look at it. This one has brilliant green eyes."
@@ -263,6 +257,7 @@
 					var/obj/structure/spider/eggcluster/C = new /obj/structure/spider/eggcluster(src.loc)
 					C.faction = faction.Copy()
 					C.master_commander = master_commander
+					C.xenobiology_spawned = xenobiology_spawned
 					if(ckey)
 						C.player_spiders = 1
 					fed--

code/modules/mob/living/simple_animal/simple_animal.dm

@@ -80,6 +80,8 @@
 	var/max_offspring = DEFAULT_MAX_OFFSPRING
 
 	var/buffed = 0 //In the event that you want to have a buffing effect on the mob, but don't want it to stack with other effects, any outside force that applies a buff to a simple mob should at least set this to 1, so we have something to check against
+	///Was this mob spawned by xenobiology magic? Used for mobcapping.
+	var/xenobiology_spawned = FALSE
 	var/gold_core_spawnable = NO_SPAWN //If the mob can be spawned with a gold slime core. HOSTILE_SPAWN are spawned with plasma, FRIENDLY_SPAWN are spawned with blood
 
 	var/mob/living/carbon/human/master_commander = null //holding var for determining who own/controls a sentient simple animal (for sentience potions).
@@ -374,6 +376,8 @@
 			visible_message("<span class='danger'>\The [src] [deathmessage]</span>")
 		else if(!del_on_death)
 			visible_message("<span class='danger'>\The [src] stops moving...</span>")
+	if(xenobiology_spawned)
+		SSmobs.xenobiology_mobs--
 	if(del_on_death)
 		//Prevent infinite loops if the mob Destroy() is overridden in such
 		//a manner as to cause a call to death() again