[ENHANCEMENT] Ability to prevent the Freeplay Song preview from playing

[KoloInDaCrib]

Linked Issues

N/A

Description

There has been a big debate whether or not having the song labelled as "NEW" should prevent the preview from being played or not. This PR provides an alternative solution so that both parties are satisfied.
If the song's script has a function override canPlayPreview (with params being the same as with isSongNew), with the return false, the freeplay song preview would be replaced by the Random track. However, if multiple songs in a row have canPlayPreview disabled, the 'Random' track wouldn't get reset.

Script Example

import funkin.play.song.Song;
class PhillyNiceSong extends Song
{
	public function new() {
		super('philly-nice');
	}

	public override function canPlayPreview(currentDifficulty:String, currentVariation:String):Bool {
		return false;
	}
}

Screenshots/Videos

random.is.awesome.mp4