Replace Matrix3 with System.Numerics.Matrix3x2 (#27443)

Replace Matrix3 with Matrix3x2

Content.Client/Overlays/StencilOverlay.cs

@@ -1,3 +1,4 @@
+using System.Numerics;
 using Content.Client.Parallax;
 using Content.Client.Weather;
 using Content.Shared.Salvage;
@@ -72,6 +73,6 @@ public sealed partial class StencilOverlay : Overlay
         }
 
         args.WorldHandle.UseShader(null);
-        args.WorldHandle.SetTransform(Matrix3.Identity);
+        args.WorldHandle.SetTransform(Matrix3x2.Identity);
     }
 }