Force a realm refresh after migration

This really shouldn't have much effect as it will be run in the first
`Update` method and is probably a noop (we are already pointing to the
newest version due to just performing writes), but seems like a safe addition.

In general `Realm.Refresh()` only really does anything when there's multithreaded
usage and notifications to be sent.

osu.Game/Database/EFToRealmMigrator.cs

@@ -42,6 +42,9 @@ namespace osu.Game.Database
                 migrateScores(ef);
             }
 
+            Logger.Log("Refreshing realm...", LoggingTarget.Database);
+            realmContextFactory.Refresh();
+
             // Delete the database permanently.
             // Will cause future startups to not attempt migration.
             Logger.Log("Migration successful, deleting EF database", LoggingTarget.Database);