remove some unnecessary Boolean checks

- checks for true/false and nullptr

src/Gui/propertyeditor/PropertyModel.cpp

@@ -245,7 +245,7 @@ static PropertyItem *createPropertyItem(App::Property *prop)
 PropertyModel::GroupInfo &PropertyModel::getGroupInfo(App::Property *prop)
 {
     const char* group = prop->getGroup();
-    bool isEmpty = (group == nullptr || group[0] == '\0');
+    bool isEmpty = (!group || group[0] == '\0');
     QString groupName = QString::fromLatin1(
             isEmpty ? QT_TRANSLATE_NOOP("App::Property", "Base") : group);