fix DatePicker ref typing

[acfasj]

[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

close #31985

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English	Fix DatePicker ref typing
🇨🇳 Chinese	修复 DatePicker ref 类型

☑️ Self Check before Merge

⚠️ Please check all items below before review. ⚠️

• 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]

[codecov]

Codecov Report

Merging #31993 (ed20d2f) into master (16d1bc8) will not change coverage.
The diff coverage is 100.00%.

❗ Current head ed20d2f differs from pull request most recent head 4e4ffff. Consider uploading reports for the commit 4e4ffff to get more accurate results

@@            Coverage Diff            @@
##            master    #31993   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          399       399           
  Lines         7592      7592           
  Branches      2080      2080           
=========================================
  Hits          7592      7592           

Impacted Files	Coverage Δ
...date-picker/generatePicker/generateRangePicker.tsx	100.00% <100.00%> (ø)
...ate-picker/generatePicker/generateSinglePicker.tsx	100.00% <100.00%> (ø)
components/date-picker/generatePicker/index.tsx	100.00% <100.00%> (ø)

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