account for itsme maybe returning empty SAML attributes (#45925)

src/authentic2_auth_fedict/adapters.py

@@ -167,6 +167,8 @@ class AuthenticAdapter(DefaultAdapter):
             user.is_active = False
             user.save()
 
+        nrn = None
+        if saml_attributes.get('egovNRN'):
             nrn = saml_attributes['egovNRN'][0]
             for attr_name in ('niss', 'nrn'):
                 try: