Fix incorrect selection restore code in split case

The fallback to "any of the added sets" needs to be applied after
they've all been added, rather than with every added one. Otherwise, in
flows that expect a particular difficulty to be selected in the end
(such as exiting from editor) would end up switching away from the
edited beatmap.

osu.Game/Screens/Select/BeatmapCarousel.cs

@@ -419,6 +419,8 @@ namespace osu.Game.Screens.Select
 
             if (beatmapsSplitOut)
             {
+                var newSets = new List<CarouselBeatmapSet>();
+
                 foreach (var beatmap in beatmapSet.Beatmaps)
                 {
                     var newSet = createCarouselSet(new BeatmapSetInfo(new[] { beatmap })
@@ -429,13 +431,18 @@ namespace osu.Game.Screens.Select
 
                     if (newSet != null)
                     {
+                        newSets.Add(newSet);
                         root.AddItem(newSet);
-
-                        // check if we can/need to maintain our current selection.
-                        if (previouslySelectedID != null)
-                            select((CarouselItem?)newSet.Beatmaps.FirstOrDefault(b => b.BeatmapInfo.ID == previouslySelectedID) ?? newSet);
                     }
                 }
+
+                // check if we can/need to maintain our current selection.
+                if (previouslySelectedID != null)
+                {
+                    var toSelect = newSets.FirstOrDefault(s => s.Beatmaps.Any(b => b.BeatmapInfo.ID == previouslySelectedID))
+                                   ?? newSets.FirstOrDefault();
+                    select(toSelect);
+                }
             }
             else
             {