Fixed type of a default value of HamburgerMenu.OpenPanelLength

Author: snrnats

Microsoft.Toolkit.Uwp.UI.Controls/HamburgerMenu/HamburgerMenu.Properties.cs

@@ -25,7 +25,7 @@ public partial class HamburgerMenu
         /// <summary>
         /// Identifies the <see cref="OpenPaneLength"/> dependency property.
         /// </summary>
-        public static readonly DependencyProperty OpenPaneLengthProperty = DependencyProperty.Register(nameof(OpenPaneLength), typeof(double), typeof(HamburgerMenu), new PropertyMetadata(320));
+        public static readonly DependencyProperty OpenPaneLengthProperty = DependencyProperty.Register(nameof(OpenPaneLength), typeof(double), typeof(HamburgerMenu), new PropertyMetadata(320.0));
 
         /// <summary>
         /// Identifies the <see cref="PanePlacement"/> dependency property.