Muse Dash: Change AttributeError to KeyError when Create_Item receive…

…s an item name that doesn't exist in the world (ArchipelagoMW#4215)

* Change missing attribute error to key error.

* Swap to explicit key error

* Revert "Swap to explicit key error"

This reverts commit 7192558.

worlds/musedash/__init__.py

@@ -183,7 +183,7 @@ def create_item(self, name: str) -> Item:
         if album:
             return MuseDashSongItem(name, self.player, album)
 
-        song = self.md_collection.song_items.get(name)
+        song = self.md_collection.song_items[name]
         return MuseDashSongItem(name, self.player, song)
 
     def get_filler_item_name(self) -> str: