This reverts commit f3faad74d5, reversing
changes made to 712e7bc7bf.
Several issues arose after migrating to 5.0, including, but possibly not
limited to, performance regressions in song select, as well as failures
when attempting to save beatmaps after metadata changes in the editor.
I'm fixing this in the simplest way possible as this kind of issue is
specific to EF core, which may cease to exist quite soon. Turns out the
re-retrieval of the beatmap set causes concurrency confusion and wasn't
actually needed in my final iteration of the new beatmap logic.