Use image@2x from tournament banner api

osu.Game.Tests/Visual/Online/TestSceneUserProfileOverlay.cs

@@ -126,6 +126,7 @@ namespace osu.Game.Tests.Visual.Online
                 Id = 13926,
                 TournamentId = 35,
                 ImageLowRes = "https://assets.ppy.sh/tournament-banners/official/owc2022/profile/winner_US.jpg",
+                Image = "https://assets.ppy.sh/tournament-banners/official/owc2022/profile/winner_US@2x.jpg",
             },
             Badges = new[]
             {

osu.Game/Users/TournamentBanner.cs

@@ -1,7 +1,6 @@
 // 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 System.IO;
 using Newtonsoft.Json;
 
 namespace osu.Game.Users
@@ -17,7 +16,7 @@ namespace osu.Game.Users
         [JsonProperty("image")]
         public string ImageLowRes = null!;
 
-        // TODO: remove when api returns @2x image link: https://github.com/ppy/osu-web/issues/9816
-        public string Image => $@"{Path.ChangeExtension(ImageLowRes, null)}@2x{Path.GetExtension(ImageLowRes)}";
+        [JsonProperty("image@2x")]
+        public string Image = null!;
     }
 }