fix():修复没有验证码的情况下，直接返回构造模式的构造对象的情况

src/main/java/com/muyu/gateway/service/impl/ValidateCodeServiceImpl.java

@@ -50,7 +50,7 @@ public class ValidateCodeServiceImpl implements ValidateCodeService {
         CaptchaCodeResp.CaptchaCodeRespBuilder respBuilder = CaptchaCodeResp.builder()
                 .captchaEnabled(captchaEnabled);
         if (!captchaEnabled) {
-            return Result.success(respBuilder);
+            return Result.success(respBuilder.build());
         }
 
         // 保存验证码信息