fix: avoid duplicate event handlers after chart remake

[xuefei1313]

🤔 This is a ...

• Bug fix
• New feature
• TypeScript definition update
• Bundle size optimization
• Performance optimization
• Enhancement feature
• Refactoring
• Update dependency
• Code style optimization
• Test Case
• Branch merge
• Release
• Site / documentation update
• Demo update
• Workflow
• Other (about what?)

🔗 Related issue link

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🔗 Related PR link

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🐞 Bugserver case id

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💡 Background and solution

当 pointerdown 用户回调中调用 updateSpec，且更新触发图表重建时，VChart 会重复回放已注册的用户事件，因此后续点击会额外触发回调。

重建时不再回放仍由 VChart 全局事件实例持有的用户监听；同时释放旧 chart-owned Event 的内部监听，避免 interaction 等模块在重建后重复注册。不会清空共享 EventDispatcher，因此不会影响其他模块或用户事件。

新增回归测试、chart 事件释放测试，以及 browser 复现页。

📝 Changelog

Language	Changelog
🇺🇸 English	fix: prevent duplicate event callbacks after updateSpec remakes a chart
🇨🇳 Chinese	fix: 修复 updateSpec 重建图表后用户事件回调重复触发的问题

☑️ Self-Check before Merge

• Doc is not needed
• Demo is provided
• TypeScript definition is not needed
• Changelog is provided

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🚀 Summary

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🔍 Walkthrough

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