fix: Tree switcherIcon prop not working when showLine

[MrHeer]

🤔 This is a ...

• New feature
• Bug fix
• Site / document update
• Component style update
• TypeScript definition update
• Refactoring
• Code style optimization
• Test Case
• Branch merge
• Other (about what?)

🔗 Related issue link

close #18810

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English	🐛 Fix Tree switcherIcon prop not working when showLine is true
🇨🇳 Chinese	🐛 修修复当 showLine 设置后 Tree 组件的 switcherIcon 属性没有正常工作

☑️ Self Check before Merge

• 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

[netlify]

Deploy preview for ant-design ready!

Built with commit d903b7c

https://deploy-preview-18829--ant-design.netlify.com

[afc163]

来个用例？

[afc163]

close #18717 too

[MrHeer]

I just fix this bug, no feature for #18717

[codecov]

Codecov Report

Merging #18829 into master will decrease coverage by 0.02%.
The diff coverage is 66.66%.

@@            Coverage Diff             @@
##           master   #18829      +/-   ##
==========================================
- Coverage   96.91%   96.88%   -0.03%     
==========================================
  Files         281      281              
  Lines        7546     7546              
  Branches     2102     2105       +3     
==========================================
- Hits         7313     7311       -2     
- Misses        231      233       +2     
  Partials        2        2

Impacted Files	Coverage Δ
components/tree/Tree.tsx	90.62% <66.66%> (-6.25%)	⬇️
components/_util/responsiveObserve.ts	100% <0%> (ø)	⬆️
components/layout/Sider.tsx	95.6% <0%> (ø)	⬆️
components/carousel/index.tsx	96.55% <0%> (ø)	⬆️

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[ywy94ywy]

修复了吗？我什么我还是无法更改，我希望是这样子的