I tried also updating the colours to the "new" versions from designs but
they don't match due to colour profile differences (so I'm not yet sure
if they are correct or not) and also don't look great without all the UI
elements also being updated.
There were cases in the editor where rewinding of transforms would
leave the `DrawableHitObject` in a non-`IsPresent` state, resulting in
this scheduled logic never running.
This would in turn cause ghost hitobjects, which disappear under certain
circumstances.
Reproduction:
- Open editor to empty beatmap
- Place single hitcircle at current point in time
- Drag editor timeline backwards to seek before zero, and wait for
return to zero
- Select hitcircle in playfield
- Drag hitcircle to right in timeline, triggering a start time change
This was firing regardless of whether the start time was changed, such
as where beat snap provided the same time the object already has.
The case where a change actually occurs is already handled by
EditorBeatmap (see `startTimeBindables`), so it turns out this local
handling is not required at all.