Regressed in https://github.com/ppy/osu/pull/28399.
To reproduce, enter a playlist that has an item with a rate-changing mod
(rather than create it yourself).
This is happening because `APIRuleset` has `CreateInstance()`
unimplemented:
b4cefe0cc2/osu.Game/Online/API/Requests/Responses/APIBeatmap.cs (L159)
and only triggers when the playlist items in question originate from
web.
This is why it is bad to have interface implementations throw outside of
maybe mock implementations for tests. `CreateInstance()` is a scourge
elsewhere in general, we need way less of it in the codebase (because
while convenient, it's also problematic to implement in online contexts,
and also expensive because reflection).
0d2a47167c