Make it possible to disable ExpandableComponent

It won't show the drop-down icon then, won't do hovers and won't allow you to click on it. This will not remove the contents of the ExpandableComponent menu bar item though, so that has to be done in ConfigurationMenu.qml.

Contributes to issue CURA-5876.

resources/qml/ExpandableComponent.qml

@@ -32,6 +32,8 @@ Item
     property color headerBackgroundColor: UM.Theme.getColor("action_button")
     property color headerHoverColor: UM.Theme.getColor("action_button_hovered")
 
+    property alias enabled: mouseArea.enabled
+
     // Defines the alignment of the popup with respect of the headerItem, by default to the right
     property int popupAlignment: ExpandableComponent.PopupAlignment.AlignRight
 
@@ -139,7 +141,7 @@ Item
                 verticalCenter: parent.verticalCenter
                 margins: background.padding
             }
-            visible: source != ""
+            visible: source != "" && base.enabled
             width: height
             height: Math.round(0.2 * base.height)
             color: UM.Theme.getColor("text")

resources/qml/Menus/ConfigurationMenu/ConfigurationMenu.qml

@@ -45,6 +45,7 @@ Cura.ExpandableComponent
             orientation: ListView.Horizontal
             anchors.fill: parent
             model: extrudersModel
+            visible: base.enabled
 
             delegate: Item
             {