Fix osu! logo suddenly disappearing during rapid exit

[bdach]

master:

2023-07-30.19-06-14.mp4

this PR:

2023-07-30.19-06-45.mp4

That particular part regressed in #24208. tl;dr: MainMenu wasn't returning the proxy to game on exit. Note that reproduction requires that any screen under MainMenu is navigated to; exiting from MainMenu itself will look fine.

You might ask why this isn't a problem if you exit slowly, but only shows up when exiting quickly; I have no idea after several hours of staring at ScreenStack. I got about as far as determining that during a slow exit, main menu will only be expired, but during a fast exit, it will be expired and then removed from hierarchy entirely. I don't know why.

I also don't know why this rotation doesn't play out all of the time. The kiai fountain PR didn't break that so I'm cutting my losses there. There's probably something that should be fixed in ScreenStack or in the weird logo arriving-suspending-exiting management flow but I'm attempting to be pragmatic here. If reviewers think that this PR is too much of a shortcut, then this can be closed I guess. Help debugging these complex systems would certainly be appreciated because I give up right now.

[bdach]

Storing this is required because if you exit very fast, you can hit LogoExiting() without a prior LogoArriving(), thus dying at

Unhandled exception. System.InvalidOperationException: No usage to return
   at osu.Game.Screens.Menu.OsuLogo.ReturnProxy() in /home/dachb/Documents/opensource/osu/osu.Game/Screens/Menu/OsuLogo.cs:line 461
   at osu.Game.Screens.Menu.MainMenu.LogoExiting(OsuLogo logo) in /home/dachb/Documents/opensource/osu/osu.Game/Screens/Menu/MainMenu.cs:line 271
   at osu.Game.Screens.OsuScreen.<onExitingLogo>b__80_0() in /home/dachb/Documents/opensource/osu/osu.Game/Screens/OsuScreen.cs:line 265
   at osu.Game.Screens.Menu.OsuLogo.<>c__DisplayClass39_0.<AppendAnimatingAction>g__runnableAction|0() in /home/dachb/Documents/opensource/osu/osu.Game/Screens/Menu/OsuLogo.cs:line 256
   at osu.Game.Screens.Menu.OsuLogo.AppendAnimatingAction(Action action, Boolean waitForPrevious) in /home/dachb/Documents/opensource/osu/osu.Game/Screens/Menu/OsuLogo.cs:line 261
   at osu.Game.Screens.OsuScreen.onExitingLogo() in /home/dachb/Documents/opensource/osu/osu.Game/Screens/OsuScreen.cs:line 265
   at osu.Game.Screens.OsuScreen.OnExiting(ScreenExitEvent e) in /home/dachb/Documents/opensource/osu/osu.Game/Screens/OsuScreen.cs:line 230
   at osu.Game.Screens.Menu.MainMenu.OnExiting(ScreenExitEvent e) in /home/dachb/Documents/opensource/osu/osu.Game/Screens/Menu/MainMenu.cs:line 334
   at osu.Framework.Screens.ScreenStack.exitFrom(IScreen source, Boolean shouldFireExitEvent, Boolean shouldFireResumeEvent, IScreen destination)
   at osu.Framework.Screens.ScreenStack.Exit(IScreen source)
   at osu.Framework.Screens.ScreenExtensions.Exit(IScreen screen)
   at osu.Game.Screens.Menu.MainMenu.<OnExiting>b__62_0() in /home/dachb/Documents/opensource/osu/osu.Game/Screens/Menu/MainMenu.cs:line 318

Alternative would be making ReturnProxy() safely re-entrant I guess.

The reason why it is possible to receive exit without arrival is that resume-arrival gets appended to queue of actions potentially queued by previous screen, which exit disregards in favour of performing actions immediately:

osu/osu.Game/Screens/OsuScreen.cs

Lines 255 to 266 in a6343a6

	private void applyArrivingDefaults(bool isResuming)
	{
	logo?.AppendAnimatingAction(() =>
	{
	if (this.IsCurrentScreen()) LogoArriving(logo, isResuming);
	}, true);
	}
	private void onExitingLogo()
	{
	logo?.AppendAnimatingAction(() => LogoExiting(logo), false);
	}