Slider heads are guaranteed to always be drawn at (0,0). This fixes
weird behaviour in the editor, but also simplifies things in the
process. Win-win.
Closes#20644.
Stable would dim objects when they can't be hit (ie. the "miss" window
is not active yet). This was never implemented in lazer, and causes
quite large visual differences.
No one has mentioned this yet, but it will definitely be one of those
missing pieces which makes lazer feel different to stable.
Aims to make minimal changes to `DrawableSlider` itself. I'm not super
happy about the slider ball being moved above the head circle, but it
*is* what people are used to so no one except for me is going to
complain.
Supersedes and closes https://github.com/ppy/osu/pull/14561.