do not set a password on FranceConnect users (#25535)

As user don't know this password they can never change it...

src/authentic2_auth_fc/app_settings.py

@@ -70,7 +70,6 @@ class AppSettings(object):
             'last_name': 'family_name',
             'first_name': 'given_name',
             'email': 'email',
-            'password': {'compute': 'random', 'if-empty': True},
         })
 
     @property

tests/test_auth_fc.py

@@ -109,9 +109,6 @@ def test_login(app, fc_settings, caplog, exp):
         # we must be connected
         assert app.session['_auth_user_id']
         assert models.FcAccount.objects.count() == 1
-        # by default we set a random password on new users, so they can use the
-        # recover my password form
-        assert User.objects.get().has_usable_password()
         response = app.get('/accounts/')
         response = response.click('Delete link')
         response.form.set('new_password1', 'ikKL1234')