this makes it easier to edit hitsounds in the stable editor after export because the sample control point effects wont get overwritten by the properties of the hitobject
The editor doesn't currently propagate velocity to nested objects. We're
not yet sure whether it should or not. For now, let's just ignore nested
objects' `DifficultyControlPoints` for simplicity.
Note that this only affects osu! ruleset due to the pre-check on
`isOsuRuleset`.