Revert "Remove some BUI boilerplate" (#30214)

Revert "Remove some BUI boilerplate (#28399)"

This reverts commit cbf329a82d.

Content.Client/MagicMirror/MagicMirrorBoundUserInterface.cs

@@ -1,7 +1,6 @@
 using Content.Shared.Humanoid.Markings;
 using Content.Shared.MagicMirror;
 using Robust.Client.GameObjects;
-using Robust.Client.UserInterface;
 
 namespace Content.Client.MagicMirror;
 
@@ -18,7 +17,7 @@ public sealed class MagicMirrorBoundUserInterface : BoundUserInterface
     {
         base.Open();
 
-        _window = this.CreateWindow<MagicMirrorWindow>();
+        _window = new();
 
         _window.OnHairSelected += tuple => SelectHair(MagicMirrorCategory.Hair, tuple.id, tuple.slot);
         _window.OnHairColorChanged += args => ChangeColor(MagicMirrorCategory.Hair, args.marking, args.slot);
@@ -30,6 +29,9 @@ public sealed class MagicMirrorBoundUserInterface : BoundUserInterface
             args => ChangeColor(MagicMirrorCategory.FacialHair, args.marking, args.slot);
         _window.OnFacialHairSlotAdded += delegate () { AddSlot(MagicMirrorCategory.FacialHair); };
         _window.OnFacialHairSlotRemoved += args => RemoveSlot(MagicMirrorCategory.FacialHair, args);
+
+        _window.OnClose += Close;
+        _window.OpenCentered();
     }
 
     private void SelectHair(MagicMirrorCategory category, string marking, int slot)
@@ -63,5 +65,14 @@ public sealed class MagicMirrorBoundUserInterface : BoundUserInterface
 
         _window.UpdateState(data);
     }
+
+    protected override void Dispose(bool disposing)
+    {
+        base.Dispose(disposing);
+        if (!disposing)
+            return;
+
+        _window?.Dispose();
+    }
 }