While `EndTime + tickSpacing` _was_ closer to what stable was using, it
could cause undesirable edge cases wherein a tick would be spawned
outside of the drum roll's duration
(see https://github.com/ppy/osu/pull/23768/files#r1222073027).
For this reason, stick with the old code for now, as it is not as
susceptible to that sort of breakage.