Don't handle tab navigation in DefaultMenuInteractionHandler.

Allow the default keyboard interaction handler to handle tab key presses in menus, because the logic in `DefaultMenuInteractionHandler` was causing the focus to get stuck in the menu.

Also fix `NavigationDirection.IsDirectional` method.

Fixes #5002.

src/Avalonia.Controls/Platform/DefaultMenuInteractionHandler.cs

@@ -231,7 +231,7 @@ namespace Avalonia.Controls.Platform
                 {
                     var direction = e.Key.ToNavigationDirection();
 
-                    if (direction.HasValue)
+                    if (direction?.IsDirectional() == true)
                     {
                         if (item == null && _isContextMenu)
                         {

src/Avalonia.Input/NavigationDirection.cs

@@ -83,7 +83,7 @@ namespace Avalonia.Input
         /// </returns>
         public static bool IsDirectional(this NavigationDirection direction)
         {
-            return direction > NavigationDirection.Previous ||
+            return direction > NavigationDirection.Previous &&
                 direction <= NavigationDirection.PageDown;
         }