fix: Dropdown sub-menu missing motion

[zombieJ]

[中文版模板 / Chinese template]

🤔 This is a ...

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

🔗 Related issue link

ref #38818
close #39234

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English	Fix Dropdown sub menu missing motion.
🇨🇳 Chinese	修复 Dropdown 二级菜单丢失动画的问题。

☑️ 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

[github-actions]

[github-actions]

Size Change: -289 B (0%)

Total Size: 899 kB

Filename	Size	Change
./dist/antd-with-locales.min.js	479 kB	-77 B (0%)
./dist/antd.min.js	421 kB	-212 B (0%)

_{compressed-size-action}

[zombieJ]

神奇，加了一行代码反而体积变小了？

[codecov]

Codecov Report

Base: 100.00% // Head: 100.00% // No change to project coverage 👍

Coverage data is based on head (5a08ee3) compared to base (33e06a2).
Patch has no changes to coverable lines.

Additional details and impacted files

@@            Coverage Diff            @@
##            master    #39235   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          546       546           
  Lines         9364      9364           
  Branches      2653      2653           
=========================================
  Hits          9364      9364           

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