[hooks/security] allow edition of attributes with permissive permissions If an attribute has more permissive security rules than the entity type itself, we should be green and not deny action because of an early global entity permission check (with the more restrictive rules). Only if one attribute with the entity-level permission rules is edited will the global check be performed. Note: * the "if action == 'delete'" check at the entry of check_entity_attributes is a guard for a condition currently not happening in cubicweb itself (but application hooks could conceivably call this function with a 'delete' action) Closes #3489895.

TACHES
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-- écrire objet stocke/manipule les données

-- extraire tests de chaîne de caractère

* utiliser sqlite 

* écrire fonction prend chemin en argument et renvoie contenu

* extraire tests (chaîne de caractère) de spec 

* utiliser yams pour schéma