Fix hit testing in RectangleNode.

There were two problems here:

- As #2370 describes we were tested against the rotated AABB of the rectangle
- We were hit-testing non-filled rectangles as filled rectangles

Fixes #2370

src/Avalonia.Visuals/Rendering/SceneGraph/RectangleNode.cs

@@ -105,8 +105,28 @@ namespace Avalonia.Rendering.SceneGraph
             }
         }
 
-        // TODO: This doesn't respect CornerRadius yet.
         /// <inheritdoc/>
-        public override bool HitTest(Point p) => Bounds.Contains(p);
+        public override bool HitTest(Point p)
+        {
+            // TODO: This doesn't respect CornerRadius yet.
+            if (Transform.HasInverse)
+            {
+                p *= Transform.Invert();
+
+                if (Brush != null)
+                {
+                    var rect = Rect.Inflate((Pen?.Thickness / 2) ?? 0);
+                    return rect.Contains(p);
+                }
+                else
+                {
+                    var borderRect = Rect.Inflate((Pen?.Thickness / 2) ?? 0);
+                    var emptyRect = Rect.Deflate((Pen?.Thickness / 2) ?? 0);
+                    return borderRect.Contains(p) && !emptyRect.Contains(p);
+                }
+            }
+
+            return false;
+        }
     }
 }