Move layer.enabled inside the child item in ExtruderIcon

When it was in the outer item, it was causing the label to disappear when then extruder icon was getting disabled. Moving it inside the child item which has the opacity change seems to fix that issue.

CURA-8417

resources/qml/ExtruderIcon.qml

@@ -18,11 +18,12 @@ Item
     property bool extruderEnabled: true
     property alias iconSize: mainIcon.sourceSize
     property string iconVariant: "medium"
-    layer.enabled: true // Prevent weird opacity effects.
+
     Item
     {
         opacity: extruderEnabled ? 1 : UM.Theme.getColor("extruder_disabled").a
         anchors.fill: parent
+        layer.enabled: true // Prevent weird opacity effects.
 
         UM.RecolorImage
         {