misc: adapt string view of FC user data for py3 (#45467)

src/authentic2_cut/user_datas.py

@@ -23,7 +23,7 @@ class FranceConnectUserData(object):
         self.user = user
         self.request = request
 
-    def __unicode__(self):
+    def __str__(self):
         from authentic2_auth_fc.models import FcAccount
         if FcAccount.objects.filter(user=self.user).exists():
             return format_html(u'<p>Utilisateur relié à un compte FranceConnect</p>')
@@ -35,7 +35,7 @@ class ValidationUserData(object):
     def __init__(self, user):
         self.user = user
 
-    def __unicode__(self):
+    def __str__(self):
         context_map = {
             'FC': 'par FranceConnect',
             'office': 'au guichet',