Config names are forced to lowercase even when json files are saved without forced lowercase

Configs cause confusion due to current case handling.
Reloading configs forces their names to lowercase.

Example:
Create config `ModLoaderConfig.create_config("MyMod", "MyConfig", {}`.
Config gets saved as `MyConfig.json`.
ModLoader reloads configs.
Calling `ModLoaderConfig.get_configs("MyMod")` reveals a `default` and `myconfig` configs, and `ModLoaderConfig.get_config("MyMod", "MyConfig")` returns null.

https://github.com/GodotModding/godot-mod-loader/blob/58d05cad245233a4cc6933ddd44b7fdc62a2edf6/addons/mod_loader/resources/mod_config.gd#L27