increase z-index of BasicItem contentItem

--this way any mouseareas inside the contentItem
are higher in the z-index comparing with any mouseareas
inside the Ability.BasicItem

BUG:432386

declarativeimports/abilities/items/BasicItem.qml

@@ -282,6 +282,7 @@ Item{
     Flow{
         width: parent.width
         height: parent.height
+        z:10
 
         BasicItemParts.HiddenSpacer{ id:hiddenSpacerLeft}