Originally noticed during review of another change:
https://github.com/ppy/osu/pull/27369#issuecomment-1966140198.
`DrawableOsuHitObject` tries to solve the initial dimming of objects
by applying transform to a list of dimmable parts. For plain drawables
this is safe, but if one of the parts is a DHO, it is not safe,
because drawable transforms can be cleared at will.
In particular, on first use of a drawable slider,
`UpdateInitialTransforms()` would fire via `LoadComplete()` on the
`DrawableSlider`, but *then*, also via `LoadComplete()`,
the `DrawableSliderTail` would update its own state and by doing so
inadvertently clear the dim transform just added by the slider.
To fix, ensure dim transforms are applied to DHOs
via `ApplyCustomUpdateState`.