Allow spectator and replay gameplay to load even when window is inactive

[peppy]

This used to be the case, but recently changed with the introduction of pausing when inactive. The change was intended to work for local gameplay modes, but it makes less sense for spectator/replay where you may want to be watching in the background while doing something else.

Raised via email.

[bdach]

This doesn't work for replay-generating mods like Autoplay or Cinema. It's unclear to me whether that is intentional or not.

This is because in song select, it can be that a normal PlayerLoader (as opposed to a ReplayPlayerLoader) pushes a ReplayPlayer.

osu/osu.Game/Screens/Select/SoloSongSelect.cs

Lines 127 to 145 in c28c649

	this.Push(playerLoader = new PlayerLoader(createPlayer));
	Player createPlayer()
	{
	Player player;
	var replayGeneratingMod = Mods.Value.OfType<ICreateReplayData>().FirstOrDefault();
	if (replayGeneratingMod != null)
	{
	player = new ReplayPlayer(replayGeneratingMod.CreateScoreFromReplayData);
	}
	else
	{
	player = new SoloPlayer();
	}
	return player;
	}

If this is unintentional / broken, then I can think of the following fixes:

• Changing above code such that ReplayPlayerLoader is pushed to begin with if a replay-generating mod is present
• Exposing WindowShouldBeActiveForGameplay as public rather than protected and setting it in the broken usage site as required