fix HitErrorMeter: make ScoreProcessor nullable to prevent DI crash on async load race

Author: Copilot

osu.Game/Screens/Play/HUD/HitErrorMeters/HitErrorMeter.cs

@@ -18,7 +18,7 @@ public abstract partial class HitErrorMeter : CompositeDrawable, ISerialisableDr
     {
         protected HitWindows HitWindows { get; private set; }
 
-        [Resolved]
+        [Resolved(canBeNull: true)]
         private ScoreProcessor processor { get; set; }
 
         [Resolved]
@@ -44,7 +44,7 @@ protected override void LoadComplete()
 
             gameplayClockContainer?.OnSeek += Clear;
 
-            processor.NewJudgement += processorNewJudgement;
+            processor?.NewJudgement += processorNewJudgement;
         }
 
         // Scheduled as meter implementations are likely going to change/add drawables when reacting to this.