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

components/__tests__/AccountAdminShell.test.tsx

@@ -6,8 +6,8 @@ vi.mock('../../context/AuthContext.tsx', () => ({
   useAuth: () => ({
     user: {
       id: 9,
-      user_login: 'account_admin',
       user_name: 'account_admin',
+      display_name: 'account_admin',
       status: 'account_admin',
       is_superuser: false,
       created_at: '',