fix: release dimension hover pointerout listener

[xuefei1313]

[中文版模板 / Chinese template]

🤔 This is a ...

• New feature
• Bug fix
• 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

N/A

🔗 Related PR link

Related to #4626.

🐞 Bugserver case id

N/A

💡 Background and solution

DimensionHoverEvent registers pointermove, pointerout, and, on mobile, pointerdown. Its unregister method did not remove the pointerout listener, so a released dimension-hover subscriber could remain referenced by the dispatcher.

This change unregisters pointerout with the same callback and adds a regression test that verifies the desktop listeners are all removed.

📝 Changelog

Language	Changelog
🇺🇸 English	Fixed a retained pointerout listener after unregistering dimension-hover events.
🇨🇳 Chinese	修复 dimension hover 事件注销后遗留 pointerout 监听的问题。

☑️ Self-Check before Merge

⚠️ Please check all items below before requesting a reviewing. ⚠️

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

---

🚀 Summary

copilot:summary

🔍 Walkthrough

copilot:walkthrough