As proposed at https://github.com/ppy/osu/discussions/16936. Spotlights
are intended to have focus, so let's make sure they are the first thing
the user sees for the time being.
In the case where the background image of individual difficulties is
different, querying the beatmap *set*'s metadata as we were will cause
issues.
I haven't added test coverage for this but can if required. Can be
manually tested using https://osu.ppy.sh/beatmapsets/1595773#osu/3377474
(specifically the highest difficulty).
Closes https://github.com/ppy/osu/discussions/16873.
Completely aware that this isn't how it should be done, but would like
to get this out in a hotfix release today. Maybe changes opinions on
https://github.com/ppy/osu/pull/16890 structure?