Merge pull request #18928 from peppy/fix-realm-collection-modified

Fix one more case of collection modification during enumeration

osu.Game/Database/RealmAccess.cs

@@ -132,7 +132,7 @@ namespace osu.Game.Database
                     Logger.Log(@$"Opened realm ""{updateRealm.Config.DatabasePath}"" at version {updateRealm.Config.SchemaVersion}");
 
                     // Resubscribe any subscriptions
-                    foreach (var action in customSubscriptionsResetMap.Keys)
+                    foreach (var action in customSubscriptionsResetMap.Keys.ToArray())
                         registerSubscription(action);
                 }