Previously, for lazer scores, the ID returned from `osu-web` was
discarded and replaced with -1, due to the fact that the appropriate
structures for unification with stable, as well as unification across
solo and multiplayer, were not in place yet.
Now we're at the point where scores from all the aforementioned sources
receive a `solo_scores` DB row, and as such, we can start treating
`solo_scores`-scheme IDs as canonical "online IDs" for a score.
Mostly places that can interact with imported replays.
There are other places that use the online ID as a sort tiebreaker, or
to check presence of a score on results screens, but they should
probably still continue to only use `OnlineID`, since all scores with a
legacy online ID should have an online ID, but the converse is not
generally true.
It wasn't correctly checking the current underlying health, which could
be zero in usages of `AccumulatingHealthProcessor`, for instance.
Closes#25046.