Allow the player to advance to the next stage

[KirbyComment]

Most games boot you out of the game after clearing the stage when using thprac's practice settings. There should be a feature where it does let you advance to the next stage after beating the stage boss. This is presumably something that's not the case currently in games where you use the practice options from the Stage Practice menu, as games like GFW (that lack Stage Practice) already let you advance.