Title Screen QOL Theming

This was supposed to be a quick quality of life addition for the Title Screen that applied the save and theme to the menu, but then I discovered a new bug I had to bypass with the character palette when doing it. So I ended up doing a bit more related to the Title Screen as a result.

I also *had* a function which checks for the number of valid folders within the Pck to see how many worlds there are, but I think it might've been a bit slow so I replaced it with constant values.

- Save for the currently loaded campaign gets applied on startup
- Backing out of World 9 and over keeps you on said worlds at the title screen
- Added Skyland and Volcano to SMB1 themes since it shares most of its themes with Lost Levels
- Fixed Title Screen Stars for the Volcano Theme

Scripts/Classes/Singletons/SaveManager.gd

@@ -113,7 +113,7 @@ func write_save_to_file(json := {}, path := "") -> void:
 	file.close()
 
 func apply_save(json := {}) -> void:
-	Global.world_num = clamp(json["World"], 1, 8)
+	Global.world_num = json.get_or_add("World", 1)
 	Global.level_num = json.get_or_add("Level", 1)
 	Global.lives = json["Lives"]
 	Global.coins = json["Coins"]