[Bug] Persistent settings only get applied if the options call `_ready()`

[Maaack]

If someone were to put these buttons in a scene that doesn't necessarily get loaded during the game start loop, then the settings from the Config static class won't get applied.

This is probably solvable with an autoload or a default opening scene that initializes all the settings.
Here's an example method that could initialize the audio busses.
https://github.com/Maaack/Godot-Game-Template/blob/532dca539dcbe7a80af0fca1d9becc9bdf0e9a8e/addons/maaacks_game_template/base/scripts/app_settings.gd#L109