[MIRROR] More deletion cleanup (#1112)

* More deletion cleanup (#53681)

- Observer mobs not delling correctly
- AI delling basically nothing
- pods not delling glow effect
- minor slime cleanup

* More deletion cleanup

Co-authored-by: TiviPlus <57223640+TiviPlus@users.noreply.github.com>

code/datums/spawners_menu.dm

@@ -6,6 +6,11 @@
 		qdel(src)
 	owner = new_owner
 
+/datum/spawners_menu/Destroy()
+	owner = null
+	return ..()
+
+
 /datum/spawners_menu/ui_state(mob/user)
 	return GLOB.observer_state