SubResourceController: allow using sort object

solidify-controller/src/main/java/ch/unige/solidify/controller/SubResourceController.java

@@ -48,11 +48,6 @@ public abstract class SubResourceController<T extends Resource<T> & SubResourceC
   @GetMapping
   public HttpEntity<Collection<V>> list(@PathVariable String parentid, @ModelAttribute V filterItem,
           Pageable pageable) {
-    if (pageable.getSort().isSorted()) {
-      throw new UnsupportedOperationException(
-              messageService.get("error.sort.unsupported", new Object[] {
-                      getMainResourceClass().toString(), getSubResourceClass().toString() }));
-    }
     this.checkIfResourceExists(parentid);
 
     Page<V> list;