* Fix bug preventing filtering named constraints There was a bug (see issue #11843) that displayed a filter for Named constraints in the Sketcher Workbench whose toggling did not affect the UI in any way. This enables this feature by checking if a given constraint has a custom name or not and then appropriately toggling its visibility. * Use `std::string::empty()` per reviewer suggestion Co-authored-by: Benjamin Nauck <benjamin@nauck.se> --------- Co-authored-by: Chris Hennes <chennes@pioneerlibrarysystem.org> Co-authored-by: Benjamin Nauck <benjamin@nauck.se>