Use MobileForm.FormSpinBoxDelegate for SpinBox in proxy page

src/qml/Settings/NetworkProxyPage.qml

@@ -70,20 +70,12 @@ Kirigami.ScrollablePage {
                         proxyConfigChanged = true
                     }
                 }
-                // we probably still need a FormSpinBoxDelegate
-                MobileForm.AbstractFormDelegate {
-                    Layout.fillWidth: true
-                    contentItem: RowLayout {
-                        QQC2.Label {
-                            text: i18n("Port")
-                            Layout.fillWidth: true
-                        }
-                        QQC2.SpinBox {
+                MobileForm.FormSpinBoxDelegate {
                     id: portField
+                    label: i18n("Port")
                     value: Config.proxyPort
                     from: 0
                     to: 65536
-                            validator: IntValidator {bottom: portField.from; top: portField.to}
                     textFromValue: function(value, locale) {
                         return value // it will add a thousands separator if we don't do this, not sure why
                     }
@@ -91,8 +83,6 @@ Kirigami.ScrollablePage {
                         proxyConfigChanged = true
                     }
                 }
-                    }
-                }
                 MobileForm.FormTextFieldDelegate {
                     id: userField
                     label: i18n("User")