Fix slider end circles not remaining for long enough when hit animations disabled

[peppy]

master:

osu.2025-01-02.at.09.56.44.mp4

this pr:

osu.2025-01-02.at.09.55.43.mp4

[bdach]

Test failure is relevant - prolonging the lifetime of DrawableSlider now makes it selectable for longer, notably also after the body has faded out and only the slider tail marker is visible.

I'm not sure whether that is intended or not. Should we want to fix this, something like this is slightly dodgy but appears to mostly work:

diff --git a/osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderSelectionBlueprint.cs b/osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderSelectionBlueprint.cs
index 3504954bec..740862c9fd 100644
--- a/osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderSelectionBlueprint.cs
+++ b/osu.Game.Rulesets.Osu/Edit/Blueprints/Sliders/SliderSelectionBlueprint.cs
@@ -626,7 +626,7 @@ private void convertToStream()
 
         public override bool ReceivePositionalInputAt(Vector2 screenSpacePos)
         {
-            if (BodyPiece.ReceivePositionalInputAt(screenSpacePos))
+            if (BodyPiece.ReceivePositionalInputAt(screenSpacePos) && DrawableObject.Body.Alpha > 0)
                 return true;
 
             if (ControlPointVisualiser == null)

[bdach]

As above

whoops that was not supposed to be an approval.

[peppy]

Change seems good, have applied verbatim.