feat: Add skeleton button

[Rustin170506]

🤔 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

#18237

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English	Add skeleton button
🇨🇳 Chinese	新增骨架按钮

☑️ 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

---

View rendered components/skeleton/demo/button.md
View rendered components/skeleton/index.en-US.md
View rendered components/skeleton/index.zh-CN.md

[tests-checker]

Could you please add tests to make sure this change works as expected?

[netlify]

Deploy preview for ant-design ready!

Built with commit 977a5d4

https://deploy-preview-19699--ant-design.netlify.com

[codecov]

Codecov Report

Merging #19699 into 4.0-prepare will increase coverage by 0.03%.
The diff coverage is 100%.

@@               Coverage Diff               @@
##           4.0-prepare   #19699      +/-   ##
===============================================
+ Coverage        97.46%   97.49%   +0.03%     
===============================================
  Files              288      291       +3     
  Lines             7219     7231      +12     
  Branches          1957     1996      +39     
===============================================
+ Hits              7036     7050      +14     
+ Misses             183      181       -2

Impacted Files	Coverage Δ
components/skeleton/Button.tsx	100% <100%> (ø)
components/skeleton/Skeleton.tsx	100% <100%> (ø)
components/skeleton/index.tsx	100% <100%> (+4.34%)	⬆️
components/skeleton/Avatar.tsx	100% <100%> (ø)	⬆️
components/skeleton/SkeletonElement.tsx	100% <100%> (ø)

---

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[buildsize]

File name	Previous Size	New Size	Change
package-lock.json	973.67 KB	976.97 KB	3.3 KB (0%)

[Rustin170506]

ping~

[Rustin170506]

@zombieJ The CI failed, it seem because react-component/table react-component/table@ce44084

[zombieJ]

Let me check. Thanks

[Rustin170506]

rebased.

[yoyo837]

覆盖率不够，添加测试用例。

[Rustin170506]

覆盖率不够，添加测试用例。

已添加。

[zombieJ]

md file conflict

[Rustin170506]

md file conflict

resolved.