I think we're going to have to change this as it's quite limiting in
what you can do with osu!mania skin implementation, but for now I want
to leave a note as to why this is done, because each time I have to
trial and error check what breaks when adjusting it.
Closes https://github.com/ppy/osu/issues/22802.
Stable uses a 1,000 ms fade-in / out. Rather than matching that, I've
stuck with 500ms (what lazer was already using for the fade-in) because
I think it feels better.
Tested using the beatmap linked in the issue thread.