Hidden loadout groups (#29170)

* loadout hiding

* department of redundancy department

Content.Client/Lobby/UI/Loadouts/LoadoutWindow.xaml.cs

@@ -29,6 +29,9 @@ public sealed partial class LoadoutWindow : FancyWindow
             if (!protoManager.TryIndex(group, out var groupProto))
                 continue;
 
+            if (groupProto.Hidden)
+                continue;
+
             var container = new LoadoutGroupContainer(profile, loadout, protoManager.Index(group), session, collection);
             LoadoutGroupsContainer.AddTab(container, Loc.GetString(groupProto.Name));
             _groups.Add(container);