feat(userIdentity): 직렬화 가능하도록 수정

Author: m-a-king

src/main/java/com/somemore/global/auth/authentication/UserIdentity.java

@@ -3,13 +3,14 @@
 import com.somemore.user.domain.UserRole;
 import io.jsonwebtoken.Claims;
 
+import java.io.Serializable;
 import java.util.UUID;
 
 public record UserIdentity(
         UUID userId,
         UUID roleId,
         UserRole role
-) {
+) implements Serializable {
 
     public static UserIdentity of(UUID userId, UUID roleId, UserRole role) {
         return new UserIdentity(userId, roleId, role);