change user_name still used as login and add display_name for dashboard view instead of username on login

backend/apps/accounts/tests_scoping.py

@@ -10,19 +10,19 @@ class VisibilityScopeTests(TestCase):
     def setUp(self):
         self.client = APIClient()
         self.director = User.objects.create_user(
-            user_login="dir1", password="x", status=User.STATUS_DIRECTOR
+            user_name="dir1", password="x", status=User.STATUS_DIRECTOR
         )
         self.buh = User.objects.create_user(
-            user_login="buh1", password="x", status=User.STATUS_BUH
+            user_name="buh1", password="x", status=User.STATUS_BUH
         )
         self.buh_other = User.objects.create_user(
-            user_login="buh2", password="x", status=User.STATUS_BUH
+            user_name="buh2", password="x", status=User.STATUS_BUH
         )
         self.gm = User.objects.create_user(
-            user_login="gm1", password="x", status=User.STATUS_GM, managed_by=self.buh
+            user_name="gm1", password="x", status=User.STATUS_GM, managed_by=self.buh
         )
         self.gm_other = User.objects.create_user(
-            user_login="gm2",
+            user_name="gm2",
             password="x",
             status=User.STATUS_GM,
             managed_by=self.buh_other,
@@ -67,7 +67,7 @@ class VisibilityScopeTests(TestCase):
         self.client.force_authenticate(self.buh)
         response = self.client.get("/api/v1/users/")
         self.assertEqual(response.status_code, 200)
-        names = {row["user_name"] for row in response.data["results"]}
+        names = {row["display_name"] for row in response.data["results"]}
         self.assertEqual(names, {"gm1"})
 
     def test_gm_sees_own_city_sites_only(self):