Implement sync function for refresh button

Quite simple. There's not a lot of feedback though when you press that button. Maybe we need to look at that.

Contributes to issue CURA-8609.

resources/qml/Preferences/Materials/MaterialsSyncDialog.qml

@@ -318,6 +318,8 @@ Window
 
                                         Layout.alignment: Qt.AlignVCenter
                                         Layout.preferredWidth: width
+
+                                        onClicked: Cura.API.account.sync(true)
                                     }
                                 }
                             }