Fix LDAP directory on schema with type restriction (email) bis

org.nuxeo.ecm.directory.DirectoryException: Field type not supported in directories: email#anonymousType LDAPSession.getAttributeValue(String, Object) line: 819	
LDAPSession.createEntry(Map<String,Object>) line: 206	
LDAPSession.createEntry(DocumentModel) line: 1104	
UserManagerWithComputedGroups(UserManagerImpl).createUser(DocumentModel, DocumentModel) line: 1242	
UserManagerWithComputedGroups(UserManagerImpl).createUser(DocumentModel) line: 814	
TrialCreatorHelper.createTrialUser(DocumentPart, String) line: 82	
UserSelfRegistrationComponent$RegistrationValidator.run() line: 401	
UserSelfRegistrationComponent$RegistrationValidator(UnrestrictedSessionRunner).runUnrestricted() line: 139	
UserSelfRegistrationComponent.validateRegistration(String, String) line: 500	
UserSelfRegistrationComponent.validateRegistrationAndSendEmail(String, String, Map<String,Serializable>) line: 515	
TrialObject.validateTrialFormInternal(String, String) line: 459	
TrialObject.validateTrialForm(String, String) line: 446