Fix gameplay leaderboard not always being expanded in gameplay leaderboard

I'd have preferred a `get; init;` property but tests were also attached
at the hip to the public bindable. Without some extra composition this
is the best that I can do.

osu.Game.Tests/Visual/Gameplay/TestSceneGameplayLeaderboard.cs

@@ -36,7 +36,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             AddStep("toggle expanded", () =>
             {
                 if (leaderboard.IsNotNull())
-                    leaderboard.Expanded.Value = !leaderboard.Expanded.Value;
+                    leaderboard.ForceExpand.Value = !leaderboard.ForceExpand.Value;
             });
 
             AddSliderStep("set player score", 50, 5000000, 1222333, v => playerScore.Value = v);

osu.Game.Tests/Visual/Multiplayer/MultiplayerGameplayLeaderboardTestScene.cs

@@ -167,7 +167,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
         public void TestScoreUpdates()
         {
             AddRepeatStep("update state", UpdateUserStatesRandomly, 100);
-            AddToggleStep("switch compact mode", expanded => Leaderboard!.Expanded.Value = expanded);
+            AddToggleStep("switch compact mode", expanded => Leaderboard!.ForceExpand.Value = expanded);
         }
 
         [Test]

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorLeaderboard.cs

@@ -58,7 +58,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                     {
                         Anchor = Anchor.Centre,
                         Origin = Anchor.Centre,
-                        Expanded = { Value = true }
+                        ForceExpand = { Value = true }
                     }
                 });
             });

osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboardTeams.cs

@@ -50,7 +50,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                     Origin = Anchor.BottomCentre,
                     Team1Score = { BindTarget = LeaderboardProvider.TeamScores[0] },
                     Team2Score = { BindTarget = LeaderboardProvider.TeamScores[1] },
-                    Expanded = { BindTarget = Leaderboard!.Expanded },
+                    Expanded = { BindTarget = Leaderboard!.ForceExpand },
                 }, Add);
             });
         }

osu.Game/Screens/OnlinePlay/Multiplayer/Spectate/MultiSpectatorScreen.cs

@@ -154,7 +154,7 @@ namespace osu.Game.Screens.OnlinePlay.Multiplayer.Spectate
             });
             leaderboardFlow.Insert(0, Leaderboard = new DrawableGameplayLeaderboard
             {
-                Expanded = { Value = true }
+                ForceExpand = { Value = true }
             });
 
             LoadComponentAsync(new GameplayChatDisplay(room)

osu.Game/Screens/Play/HUD/DrawableGameplayLeaderboard.cs

@@ -20,7 +20,7 @@ namespace osu.Game.Screens.Play.HUD
 {
     public partial class DrawableGameplayLeaderboard : CompositeDrawable, ISerialisableDrawable
     {
-        public Bindable<bool> Expanded = new Bindable<bool>();
+        public readonly Bindable<bool> ForceExpand = new Bindable<bool>();
 
         protected readonly FillFlowContainer<DrawableGameplayLeaderboardScore> Flow;
 
@@ -40,7 +40,7 @@ namespace osu.Game.Screens.Play.HUD
         private readonly IBindable<LocalUserPlayingState> userPlayingState = new Bindable<LocalUserPlayingState>();
         private readonly IBindable<bool> holdingForHUD = new Bindable<bool>();
 
-        private const int max_panels = 8;
+        private readonly Bindable<bool> expanded = new Bindable<bool>();
 
         /// <summary>
         /// Create a new leaderboard.
@@ -100,6 +100,7 @@ namespace osu.Game.Screens.Play.HUD
             configVisibility.BindValueChanged(_ => Scheduler.AddOnce(updateState));
             userPlayingState.BindValueChanged(_ => Scheduler.AddOnce(updateState));
             holdingForHUD.BindValueChanged(_ => Scheduler.AddOnce(updateState));
+            ForceExpand.BindValueChanged(_ => Scheduler.AddOnce(updateState));
             updateState();
         }
 
@@ -110,7 +111,7 @@ namespace osu.Game.Screens.Play.HUD
                 scroll.ScrollToStart(false);
 
             Flow.FadeTo(player?.Configuration.ShowLeaderboard != false && configVisibility.Value ? 1 : 0, 100, Easing.OutQuint);
-            Expanded.Value = userPlayingState.Value == LocalUserPlayingState.Playing || holdingForHUD.Value;
+            expanded.Value = ForceExpand.Value || userPlayingState.Value == LocalUserPlayingState.Playing || holdingForHUD.Value;
         }
 
         /// <summary>
@@ -128,7 +129,7 @@ namespace osu.Game.Screens.Play.HUD
                 TrackedScore = drawable;
             }
 
-            drawable.Expanded.BindTo(Expanded);
+            drawable.Expanded.BindTo(expanded);
 
             Flow.Add(drawable);
             drawable.ScorePosition.BindValueChanged(_ => Scheduler.AddOnce(sort));