Materialise realm collection hashes during song select search process

Without this, there's a large overhead to do a realm-live `Contains`
search when a collection is selected.

This may also help considerably alleviate
#27298 (reply in thread)
as we will be performing the native realm search much less.

osu.Game/Screens/Select/FilterControl.cs

@@ -4,6 +4,7 @@
 #nullable disable
 
 using System;
+using System.Linq;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Graphics;
@@ -64,7 +65,7 @@ public FilterCriteria CreateCriteria()
                 Sort = sortMode.Value,
                 AllowConvertedBeatmaps = showConverted.Value,
                 Ruleset = ruleset.Value,
-                CollectionBeatmapMD5Hashes = collectionDropdown.Current.Value?.Collection?.PerformRead(c => c.BeatmapMD5Hashes)
+                CollectionBeatmapMD5Hashes = collectionDropdown.Current.Value?.Collection?.PerformRead(c => c.BeatmapMD5Hashes).ToList()
             };
 
             if (!minimumStars.IsDefault)