|Optional: The button ID to select (default: current highlighted button)
Selects the currently-highlighted button, if any, and records its ID. If a selection sound has been assigned in
vngen_button_create_ext, it will be played upon running this script.
If a button ID is supplied, it will be selected directly, ignoring navigation.
This script is not an action, and is intended to be run in keyboard and gamepad input events. Mouse and touch support are built-in and do not require
vngen_do_button_select to make selections.