fix(toast): 修复清除toast时未正确卸载组件

[betterhyq]

这个 PR 做了什么? (简要描述所做更改)
修复toast内存泄漏

这个 PR 是什么类型? (至少选择一个)

• feat: 新特性提交
• 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
• 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:

• NutUI H5 @nutui/nutui
• NutUI Taro @nutui/nutui-taro

这个 PR 是否已自测:

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

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
⚠️ Please upload report for BASE (v4@d7070c4). Learn more about missing BASE report.

Additional details and impacted files

@@          Coverage Diff          @@
##             v4    #3311   +/-   ##
=====================================
  Coverage      ?   81.84%           
=====================================
  Files         ?      226           
  Lines         ?    18163           
  Branches      ?     2528           
=====================================
  Hits          ?    14866           
  Misses        ?     3277           
  Partials      ?       20           

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