Return sponsor window to character setup

Author: Morb0

Content.Client/Lobby/UI/CharacterSetupGui.xaml.cs

@@ -1,6 +1,7 @@
 using Content.Client.Info;
 using Content.Client.Info.PlaytimeStats;
 using Content.Client.Resources;
+using Content.Corvax.Interfaces.Client;
 using Content.Shared.Preferences;
 using Robust.Client.AutoGenerated;
 using Robust.Client.Graphics;
@@ -65,6 +66,13 @@ public CharacterSetupGui(
             RulesButton.OnPressed += _ => new RulesAndInfoWindow().Open();
 
             StatsButton.OnPressed += _ => new PlaytimeStatsWindow().OpenCentered();
+            // Corvax-Sponsors-Start
+            if (IoCManager.Instance!.TryResolveType<ISponsorWindowCreator>(out var creator))
+            {
+                SponsorButton.Visible = true;
+                SponsorButton.OnPressed += _ => creator.OpenWindow();
+            }
+            // Corvax-Sponsors-End
         }
 
         /// <summary>