Replace Box(true) -> TrueBox

(cherry picked from commit 52c25da)

Author: h3xds1nz

src/Microsoft.DotNet.Wpf/src/PresentationFramework/System/Windows/Controls/GridViewColumnHeader.cs

@@ -856,7 +856,7 @@ private bool HandleIsMouseOverChanged()
                     (_headerGripper == null || !_headerGripper.IsMouseOver))
                 {
                     // Hovering over the button will click in the OnHover click mode
-                    SetValue(IsPressedPropertyKey, BooleanBoxes.Box(true));
+                    SetValue(IsPressedPropertyKey, BooleanBoxes.TrueBox);
                     OnClick();
                 }
                 else