fix: add missing using osu.Game.Audio to DrawableSlider.cs (CS0246 ISampleInfo)

Agent-Logs-Url: https://github.com/winnerspiros/osu/sessions/6590546f-8ba3-432c-af4d-2128d82c40f4

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

Author: Copilot

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

@@ -12,6 +12,7 @@
 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;