[FEM] remove more superfluous nullptr checks

src/Mod/Fem/Gui/ViewProviderFemConstraintFixed.cpp

@@ -71,7 +71,7 @@ bool ViewProviderFemConstraintFixed::setEdit(int ModNum)
         if (dlg && !constrDlg) {
             // This case will occur in the ShaftWizard application
             checkForWizard();
-            if ((wizardWidget == nullptr) || (wizardSubLayout == nullptr)) {
+            if (!wizardWidget || !wizardSubLayout) {
                 // No shaft wizard is running
                 QMessageBox msgBox;
                 msgBox.setText(QObject::tr("A dialog is already open in the task panel"));