Add a warning dialog to the observe button. (#4794)

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

@@ -0,0 +1,24 @@
+using JetBrains.Annotations;
+using Robust.Client.AutoGenerated;
+using Robust.Client.UserInterface.CustomControls;
+using Robust.Client.UserInterface.XAML;
+using Robust.Shared.IoC;
+using Robust.Shared.Localization;
+
+namespace Content.Client.Lobby.UI
+{
+    [GenerateTypedNameReferences]
+    [UsedImplicitly]
+    internal sealed partial class ObserveWarningWindow : SS14Window
+    {
+        public ObserveWarningWindow()
+        {
+            Title = Loc.GetString("observe-warning-window-title");
+            RobustXamlLoader.Load(this);
+            IoCManager.InjectDependencies(this);
+
+            ObserveButton.OnPressed += _ => { this.Close(); };
+            NevermindButton.OnPressed += _ => { this.Close(); };
+        }
+    }
+}