fix: change the prop className of the Header, Footer and Content to the last

[yoyo837]

🤔 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

ref: #21041

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English
🇨🇳 Chinese	className 放置在最后

☑️ 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

[ant-design-bot]

[codesandbox-ci]

This pull request is automatically built and testable in CodeSandbox.

To see build info of the built libraries, click here or the icon next to each commit SHA.

Latest deployment of this branch, based on commit 5af6342:

Sandbox	Source
antd reproduction template	Configuration

[codecov]

Codecov Report

Merging #21074 into master will not change coverage.
The diff coverage is 100%.

@@           Coverage Diff           @@
##           master   #21074   +/-   ##
=======================================
  Coverage   97.48%   97.48%           
=======================================
  Files         296      296           
  Lines        6911     6911           
  Branches     1871     1918   +47     
=======================================
  Hits         6737     6737           
  Misses        174      174

Impacted Files	Coverage Δ
components/layout/layout.tsx	92.1% <100%> (ø)	⬆️

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ca8ea41...5af6342. Read the comment docs.