Remove all calls to Realm.Refresh to fix blocking overhead from subscriptions

Turns out this is not required if realm is aware of a
`SynchronizationContext`. See
https://github.com/realm/realm-dotnet/discussions/2775#discussioncomment-2005412
for further reading.

osu.Game/OsuGameBase.cs

@@ -351,13 +351,6 @@ namespace osu.Game
             FrameStatistics.ValueChanged += e => fpsDisplayVisible.Value = e.NewValue != FrameStatisticsMode.None;
         }
 
-        protected override void Update()
-        {
-            base.Update();
-
-            realmFactory.Refresh();
-        }
-
         protected override IReadOnlyDependencyContainer CreateChildDependencies(IReadOnlyDependencyContainer parent) =>
             dependencies = new DependencyContainer(base.CreateChildDependencies(parent));