Improve Sort menu button's behaviors to be more conventional

Now it looks checked when clicked, and closes when menu when clicked
again.

src/qml/NavigationActionBar.qml

@@ -60,11 +60,18 @@ Item {
             id: sortMenuButton
             Kirigami.Theme.colorSet: Kirigami.Settings.isMobile ? Kirigami.Theme.Complementary : Kirigami.Theme.Window
             Kirigami.Theme.inherit: false
-            objectName: 'sortMenuButton'
             display: AbstractButton.TextOnly
+
+            checkable: true
+            checked: sortMenu.visible
+
             onClicked: {
-                sortMenu.sortOrder = navigationBar.sortOrder
-                sortMenu.popup(sortMenuButton, sortMenuButton.x, sortMenuButton.y + sortMenuButton.height)
+                if (sortMenu.visible) {
+                    sortMenu.dismiss()
+                } else {
+                    sortMenu.sortOrder = navigationBar.sortOrder
+                    sortMenu.popup(sortMenuButton, sortMenuButton.x, sortMenuButton.y + sortMenuButton.height)
+                }
             }
 
             // Custom content item for now to replicate the look of a button