core: prevent selecting a group as a parent of itself (#6016)

* core: prevent selecting a group as a parent of itself

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

* fix api error when no parent is given

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

---------

Signed-off-by: Jens Langhammer <jens@goauthentik.io>

web/src/admin/groups/GroupForm.ts

@@ -95,6 +95,9 @@ export class GroupForm extends ModelForm<Group, string> {
                             args.search = query;
                         }
                         const groups = await new CoreApi(DEFAULT_CONFIG).coreGroupsList(args);
+                        if (this.instance) {
+                            return groups.results.filter((g) => g.pk !== this.instance?.pk);
+                        }
                         return groups.results;
                     }}
                     .renderElement=${(group: Group): string => {