Reduce the serialised size of LegacyReplayFrame

osu.Game/Replays/Legacy/LegacyReplayFrame.cs

@@ -1,6 +1,7 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
+using Newtonsoft.Json;
 using osu.Game.Rulesets.Replays;
 using osuTK;
 
@@ -8,17 +9,28 @@ namespace osu.Game.Replays.Legacy
 {
     public class LegacyReplayFrame : ReplayFrame
     {
+        [JsonIgnore]
         public Vector2 Position => new Vector2(MouseX ?? 0, MouseY ?? 0);
 
         public float? MouseX;
         public float? MouseY;
 
+        [JsonIgnore]
         public bool MouseLeft => MouseLeft1 || MouseLeft2;
+
+        [JsonIgnore]
         public bool MouseRight => MouseRight1 || MouseRight2;
 
+        [JsonIgnore]
         public bool MouseLeft1 => ButtonState.HasFlag(ReplayButtonState.Left1);
+
+        [JsonIgnore]
         public bool MouseRight1 => ButtonState.HasFlag(ReplayButtonState.Right1);
+
+        [JsonIgnore]
         public bool MouseLeft2 => ButtonState.HasFlag(ReplayButtonState.Left2);
+
+        [JsonIgnore]
         public bool MouseRight2 => ButtonState.HasFlag(ReplayButtonState.Right2);
 
         public ReplayButtonState ButtonState;