bugfix：修复 HTTP TPS 限流时 metrics 采集的问题

[luky116]

Please do not create a Pull Request without creating an issue first.

What is the purpose of the change

本次 PR 修复了 HTTP TPS（每秒事务数）控制相关的两个问题：

1. 修复 Spring Boot 中 TPS 点重复注册问题：在 Spring Boot 应用中，ContextRefreshedEvent 会被触发两次 - 一次是根 ApplicationContext，一次是 Web ApplicationContext。之前的方法，优先注册的是 根 context，导致本地带了 @TpsControl 注释的方法没注册上。本次修复确保只处理根上下文，并添加了异常处理和重试能力。

2. 使用正确的 HTTP 状态码：当 TPS 超过限制时，将 HTTP 状态码从 503 (Service Unavailable) 改为 429 (Too Many Requests)，这是根据 RFC 6585 标准用于限流场景的标准 HTTP 状态码。

3. 添加 TPS 超限的 HTTP 指标记录：为 TPS 超限场景添加了 Micrometer 指标记录，以支持更好的监控和可观测性；按照之前的逻辑，如果被限流拦截，并不会记录 metrics

Brief changelog

• HttpTpsPointRegistry.java:

  • 通过检查上下文是否为根上下文（parent == null）修复重复注册问题
  • 添加异常处理和重试能力（失败时重置 isInit 标志）

• NacosHttpTpsFilter.java:

  • 将 TPS 超限响应的 HTTP 状态码从 503 改为 429
  • 添加 recordHttpMetrics() 方法使用 Micrometer 记录指标
  • 将 generate503Response() 重命名为 generate429Response() 以提高可读性

Verifying this change

1. 测试重复注册修复:

   • 在 Spring Boot 环境中启动 Nacos 服务器
   • 验证 TPS 控制点只注册一次，而不是两次
   • 检查日志确保没有重复注册警告

2. 测试 HTTP 状态码:

   • 发送超过 TPS 限制的请求
   • 验证响应状态码是 429 (Too Many Requests) 而不是 503
   • 验证响应体包含适当的错误消息

3. 测试指标记录:

   • 发送超过 TPS 限制的请求
   • 检查 Micrometer 指标端点（如果可用）或指标注册表
   • 验证 http.server.requests 计时器被记录，包含：
     • status=429
     • exception=TpsOverLimitException
     • outcome=TPS_OVER_LIMIT_ERROR
     • 正确的 method 和 uri 标签

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[github-actions]

Thanks for your this PR. 🙏
Please check again for your PR changes whether contains any usage/api/configuration change such as Add new API , Add new configuration, Change default value of configuration.
If so, please add or update documents(markdown type) in docs/next/ for repository nacos-group/nacos-group.github.io

---

感谢您提交的PR。 🙏
请再次查看您的PR内容，确认是否包含任何使用方式/API/配置参数的变更，如：新增API、新增配置参数、修改默认配置等操作。
如果是，请确保在提交之前，在仓库nacos-group/nacos-group.github.io中的docs/next/目录下添加或更新文档（markdown格式）。

[KomachiSion]

please don't change the indent

[luky116]

@KomachiSion done

[wuyfee]

$\color{red}{FAILURE}$
DETAILS
✅ - docker: success
❌ - deploy (standalone & cluster & standalone_auth): failure
❌ - e2e-java-test (standalone & cluster & standalone_auth): skipped
❌ - e2e-go-test (standalone & cluster): skipped
❌ - e2e-cpp-test (standalone & cluster): skipped
❌ - e2e-csharp-test (standalone & cluster): skipped
❌ - e2e-nodejs-test (standalone & cluster): skipped
❌ - e2e-python-test (standalone & cluster): skipped
✅ - clean (standalone & cluster & standalone_auth): success

[KomachiSion]

@luky116 CI can't pass please fix it.