hotfix: sample user login 로킹 추가

Author: Nuung

src/services/user.service.ts

@@ -95,7 +95,7 @@ export class UserService {
       user.access_token,
       user.refresh_token
     );
-
+    logger.info('샘플 유저 로그인');
     return { user, decryptedAccessToken, decryptedRefreshToken };
   }