Update overrides.lua (#1102)

Vanilla atlases do not have a `key` value, only a `name`?

Author: wingedcatgirl

src/overrides.lua

@@ -1909,7 +1909,7 @@ function create_UIBox_notify_alert(_achievement, _type)
     end
 
   if SMODS.Achievements[_achievement] then _c = SMODS.Achievements[_achievement]; _atlas = SMODS.get_atlas(_c.atlas) end
-  local t_s =  SMODS.create_sprite(0,0,1.5*(_atlas.px/_atlas.py),1.5, _atlas.key,  _c and _c.pos or {x=3, y=0})
+  local t_s =  SMODS.create_sprite(0,0,1.5*(_atlas.px/_atlas.py),1.5, _atlas.key or _atlas.name,  _c and _c.pos or {x=3, y=0})
 
   t_s.states.drag.can = false
   t_s.states.hover.can = false
@@ -2612,4 +2612,4 @@ function add_tag(_tag)
 		_tag = Tag(_tag.key, nil, _tag.blind_type)
 	end
 	add_tag_ref(_tag)
-end
+end