fix: remove unused osu.Game.Audio using in DrawableSlider.cs (IDE0005)

Agent-Logs-Url: https://github.com/winnerspiros/osu/sessions/7ba7b342-765f-428b-96e1-3925b8e2d9ab

Co-authored-by: winnerspiros <1675249+winnerspiros@users.noreply.github.com>

Author: Copilot

osu.Game.Rulesets.Osu/Objects/Drawables/DrawableSlider.cs

@@ -12,7 +12,6 @@
 using osu.Framework.Graphics;
 using osu.Framework.Graphics.Containers;
 using osu.Framework.Layout;
-using osu.Game.Audio;
 using osu.Game.Graphics.Containers;
 using osu.Game.Rulesets.Judgements;
 using osu.Game.Rulesets.Objects;
@@ -163,9 +162,6 @@ protected override void OnFree()
         protected override void LoadSamples()
         {
             // Note: base.LoadSamples() isn't called since the slider plays the tail's hitsounds for the time being.
-
-            // HitSampleInfo : ISampleInfo (reference type) — array covariance lets us cast directly,
-            // avoiding a second array allocation from .Cast<ISampleInfo>().ToArray().
             Samples.Samples = HitObject.TailSamples.ToArray();
             slidingSample.Samples = HitObject.CreateSlidingSamples().ToArray();
         }