fix(countdown): emit paused

[eiinu]

这个 PR 做了什么? (简要描述所做更改)

这个 PR 是什么类型? (至少选择一个)

• [ ] feat: 新特性提交
• [x] fix: bug 修复
• [ ] docs: 文档改进
• [ ] style: 组件样式/交互改进
• [ ] type: 类型定义更新
• [ ] perf: 性能、包体积优化
• [ ] refactor: 代码重构、代码风格优化
• [x] test: 测试用例
• [ ] chore(deps): 依赖升级
• [ ] chore(demo): 演示代码改进
• [ ] chore(locale): 国际化改进
• [ ] chore: 其他改动（是关于什么的改动？）

这个 PR 涉及以下平台:

• [x] NutUI H5 @nutui/nutui
• [x] NutUI Taro @nutui/nutui-taro

这个 PR 是否已自测:

• [x] 自测 Vite 脚手架使用 测试仓库
• [x] 自测 Taro 脚手架使用小程序 & Taro-H5 测试仓库

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 84.00%. Comparing base (0467755) to head (27cef5b).

Additional details and impacted files

```diff @@ Coverage Diff @@ ## v4 #3062 +/- ## ========================================== + Coverage 83.96% 84.00% +0.04% ========================================== Files 223 223 Lines 23039 23039 Branches 2480 2483 +3 ========================================== + Hits 19344 19354 +10 + Misses 3677 3667 -10 Partials 18 18 ```

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