Revert "feat: configure Kanban login by operator email"

This reverts commit 508fa03664.

local/smoke_test.py

@@ -30,7 +30,7 @@ class Client:
         if operator:
             if self.operator_client is None:
                 self.operator_client=Client()
-                self.operator_client.call('/operator/login',{'email':os.environ.get('OPERATOR_EMAIL','operator@example.test'),'password':os.environ.get('OPERATOR_PASSWORD','local-operator-only')})
+                self.operator_client.call('/operator/login',{'username':os.environ.get('OPERATOR_USER','operator'),'password':os.environ.get('OPERATOR_PASSWORD','local-operator-only')})
             return self.operator_client.call(path,body,expected=expected)
         request=Request(BASE+'/api'+path,data=None if body is None else json.dumps(body).encode(),headers=headers)
         try: