Bileworm post-merge feedback and qol (#69007)

* Bileworm now has a deathsound, and deathsounds now properly play on simplemobs.
* AI-controlled Bileworms now have night vision abilities

code/modules/mob/living/basic/lavaland/bileworm/_bileworm.dm

@@ -18,6 +18,7 @@
 		/obj/effect/gibspawner/generic = 1,
 		/obj/item/stack/sheet/animalhide/bileworm = 1,
 	)
+	death_message = "seizes up and falls limp, slowly receeding into its burrow with a dying gurgle..."
 
 	//it can't be dragged, just butcher it
 	move_resist = INFINITY
@@ -51,6 +52,8 @@
 	resurface.Grant(src)
 	var/datum/action/cooldown/mob_cooldown/devour/devour = new(src)
 	devour.Grant(src)
+	var/datum/action/adjust_vision/adjust_vision = new(src)
+	adjust_vision.Grant(src)
 	ai_controller.blackboard[BB_BILEWORM_SPEW_BILE] = spew_bile
 	ai_controller.blackboard[BB_BILEWORM_RESURFACE] = resurface
 	ai_controller.blackboard[BB_BILEWORM_DEVOUR] = devour

code/modules/mob/living/basic/lavaland/bileworm/bileworm_actions.dm

@@ -13,7 +13,10 @@
 	var/turf/unburrow_turf = get_unburrow_turf(burrower, target)
 	if(!unburrow_turf) // means all the turfs nearby are station turfs or something, not lavaland
 		to_chat(burrower, span_warning("Couldn't burrow anywhere near the target!"))
-		return //just put it on cooldown and let the other ability reactivate, you couldn't burrow and that's okay.
+		if(burrower.ai_controller?.ai_status == AI_STATUS_ON)
+			//this is a valid reason to give up on a target
+			burrower.ai_controller.blackboard[BB_BASIC_MOB_CURRENT_TARGET] = null
+		return
 	playsound(burrower, 'sound/effects/break_stone.ogg', 50, TRUE)
 	new /obj/effect/temp_visual/mook_dust(get_turf(burrower))
 	burrower.status_flags |= GODMODE