fix: add visibility:hidden to selector:after

[tchen-l]

[中文版模板 / Chinese template]

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• Bug fix
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🔗 Related issue link

#17334

💡 Background and solution

在某些情况下，Select会显示字母A；给-selector:after加上了visibility:hidden;样式

📝 Changelog

Language	Changelog
🇺🇸 English	In some cases, Select will display the letter A
🇨🇳 Chinese	在某些情况下，Select会显示字母A

☑️ 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
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🚀 Summary

🤖 Generated by Copilot at 1a2464c

Fix input overlap bug in multiple select component. Hide input element in components/select/style/multiple.less when the component is not focused.

🔍 Walkthrough

🤖 Generated by Copilot at 1a2464c

• Hide input element in multiple select when not focused to avoid overlap with tags and placeholder (link)

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