Fix HOC not propagating DHO results applied on kill

`DrawableHitObject.OnKilled()` calls `UpdateResult()` to clean up a
hitobject's state definitively with regards to the judgement result
before returning the DHO back to the pool.

As it turns out, if a consumer was relying on this code path (as taiko
was in the case of nested strong hit objects), it would not work
properly with pooling, due to `HitObjectContainer` unsubscribing from
`On{New,Revert}Result` *before* calling the DHO's `OnKilled()`.

This in turn would lead to users potentially getting stuck in gameplay,
due to `ScoreProcessor` not receiving all results via that event path.

To resolve, change the call ordering to allow hit result changes applied
in `OnKilled()` to propagate normally.

osu.Game/Rulesets/UI/HitObjectContainer.cs

@@ -124,9 +124,11 @@ namespace osu.Game.Rulesets.UI
             Debug.Assert(drawableMap.ContainsKey(entry));
 
             var drawable = drawableMap[entry];
+
+            // OnKilled can potentially change the hitobject's result, so it needs to run first before unbinding.
+            drawable.OnKilled();
             drawable.OnNewResult -= onNewResult;
             drawable.OnRevertResult -= onRevertResult;
-            drawable.OnKilled();
 
             drawableMap.Remove(entry);