Fix TestTouchScreenDetectionAtSongSelect test failure

https://github.com/ppy/osu/actions/runs/9985890747/job/27597501295

In this case, the settings overlay is taking a very long time to load
(on a background thread), and pops in when it finishes loading because
it's been requested to open.

The opens the settings overlay, closes it (by pressing escape, this does
not actually close it because it's not loaded yet), and then enters song
select by pressing 'P' 3 times. The settings overlay finishes loading at
just the right opportune moment to eat one of the 'P' key presses.

osu.Game.Tests/Visual/Navigation/TestSceneScreenNavigation.cs

@@ -952,6 +952,8 @@ public void TestQuickSkinEditorDoesntNukeSkin()
         [Test]
         public void TestTouchScreenDetectionAtSongSelect()
         {
+            AddUntilStep("wait for settings", () => Game.Settings.IsLoaded);
+
             AddStep("touch logo", () =>
             {
                 var button = Game.ChildrenOfType<OsuLogo>().Single();