Remove LeaderboardManager return value and simplify flow further

[peppy]

While working through #32844, it became apparent that both @frenzibyte's copy-pasted code was out of date with recent leaderboard changes, and some refactors I made were only applied local in that branch (and not to the old Leaderboard).

This attempts to resolve the issues I came across. See 1e76843 commit message for rationale.

[bdach]

I pushed a commit removing some more stuff that doesn't need to be there (also fixed a bug in the process - see if you can spot it).

There's a problem though - this breaks if you select a map, go into player loader, and then go back to menu - the leaderboard will show a spinner rather than the previous scores. This is because the criteria hasn't meaningfully changed so there's no refetch, so the global bindable has not changed value. I'm not sure what is the best way of resolving this.

Something like

diff --git a/osu.Game/Screens/Select/Leaderboards/BeatmapLeaderboard.cs b/osu.Game/Screens/Select/Leaderboards/BeatmapLeaderboard.cs
index 1c62499162..ef5608cca1 100644
--- a/osu.Game/Screens/Select/Leaderboards/BeatmapLeaderboard.cs
+++ b/osu.Game/Screens/Select/Leaderboards/BeatmapLeaderboard.cs
@@ -62,7 +62,7 @@ public bool FilterMods
             }
         }
 
-        private readonly IBindable<LeaderboardScores?> fetchedScores = new Bindable<LeaderboardScores?>();
+        private readonly Bindable<LeaderboardScores?> fetchedScores = new Bindable<LeaderboardScores?>();
 
         [Resolved]
         private IBindable<RulesetInfo> ruleset { get; set; } = null!;
@@ -102,10 +102,12 @@ private void load()
             if (!initialFetchComplete)
             {
                 // only bind this after the first fetch to avoid reading stale scores.
-                fetchedScores.BindTo(leaderboardManager.Scores);
+                ((IBindable<LeaderboardScores?>)fetchedScores).BindTo(leaderboardManager.Scores);
                 fetchedScores.BindValueChanged(_ => updateScores(), true);
                 initialFetchComplete = true;
             }
+            else
+                fetchedScores.TriggerChange();
 
             return null;
         }

seems to work but also seems to be quite dodgy.

[bdach]

Incidentally, along the similar lines as the previous comment, I'm seeing user reports like https://osu.ppy.sh/community/forums/topics/2069984?n=1, and I can believe why they're happening - the leaderboard isn't refetching after completing a play because the criteria hasn't changed either.

One way to fix this would be to just remove the early guard. (Yes you could have a force parameter or something, but as the current code structure stands you'd just be calling it with force every single time, unless more work is done to make it possible to not force every time.)

Thoughts?

[peppy]

Path of least resistance means that I agree with you. I'll adjust as such, but will leave a force parameter for future use.

[bdach]

I'm treating this as a hotfix worthy change because it's fixing a real issue of the leaderboards not refetching after returning to song select after a completed play.