Set defaultExtruderIndex to activeExtruderIndex

This doesn't fix the problem in it's entirety, but it does make the behavior
to be the same as it was in the previous releases

CURA-10342

resources/qml/Widgets/SingleSettingComboBox.qml

@@ -20,7 +20,7 @@ Cura.ComboBox {
     // The displayed value will be read from the extruder with index "defaultExtruderIndex" instead of the machine.
     property bool updateAllExtruders: false
     // This is only used if updateAllExtruders == true
-    property int defaultExtruderIndex: 0
+    property int defaultExtruderIndex: Cura.ExtruderManager.activeExtruderIndex
 
     model:  ListModel
     {

resources/qml/Widgets/SingleSettingSlider.qml

@@ -21,7 +21,7 @@ UM.Slider
     // The displayed value will be read from the extruder with index "defaultExtruderIndex" instead of the machine.
     property bool updateAllExtruders: false
     // This is only used if updateAllExtruders == true
-    property int defaultExtruderIndex: 0
+    property int defaultExtruderIndex: Cura.ExtruderManager.activeExtruderIndex
     property int previousValue: -1
 
     // set range from 0 to 100

resources/qml/Widgets/SingleSettingTextField.qml

@@ -20,7 +20,7 @@ UM.TextField
     // The displayed value will be read from the extruder with index "defaultExtruderIndex" instead of the machine.
     property bool updateAllExtruders: false
     // This is only used if updateAllExtruders == true
-    property int defaultExtruderIndex: 0
+    property int defaultExtruderIndex: Cura.ExtruderManager.activeExtruderIndex
 
     // Resolving the value in the textField.
     Binding