Align menubar colors with new designs.

CURA-8688

resources/qml/Widgets/MenuItem.qml

@@ -48,7 +48,6 @@ UM.MenuItem
         y: UM.Theme.getSize("default_lining").width
         width: menuItem.width - 2 * UM.Theme.getSize("default_lining").width
         height: menuItem.height - 2 * UM.Theme.getSize("default_lining").height
-
-        color: menuItem.highlighted ? UM.Theme.getColor("secondary"): UM.Theme.getColor("setting_control_highlight")
+        color: menuItem.highlighted ? UM.Theme.getColor("background_2"): UM.Theme.getColor("background_1")
     }
 }