Failures when attempting to create a group other than a translation group.
Steps to reproduce
Create a new group type.
Add a new group of this type.
You get this error: Drupal\Core\Entity\EntityStorageException: Field field_translation_language is unknown. in Drupal\Core\Entity\Sql\SqlContentEntityStorage->save() (line 817 of core/lib/Drupal/Core/Entity/Sql/SqlContentEntityStorage.php). This is due to missing checks in l10n_community.module at line 218 (l10n_community_group_insert()).