QmlDesigner: Prevent saving an effect with invalid name using keyboard

Fixes: QDS-11605
Change-Id: Ice1cdc715c24534d045491ede3dbfc0c3e0cbe59
Reviewed-by: Miikka Heikkinen <miikka.heikkinen@qt.io>
Reviewed-by: Qt CI Patch Build Bot <ci_patchbuild_bot@qt.io>

share/qtcreator/qmldesigner/effectMakerQmlSources/SaveAsDialog.qml

@@ -84,6 +84,9 @@ StudioControls.Dialog {
                 text: qsTr("Save")
                 enabled: nameText.text !== ""
                 onClicked: {
+                    if (!enabled) // needed since this event handler can be triggered from keyboard events
+                        return
+
                     EffectMakerBackend.effectMakerModel.saveComposition(nameText.text)
 
                     if (root.clearOnClose) {