Add @pagination-item-bg-active

[afc163]

🤔 This is a ...

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

👻 What's the background?

1. Describe the source of requirement, like related issue link.

close #14739

2. Describe the problem and the scenario.

💡 Solution

1. How to fix the problem, and list final API implementation and usage sample if that is an new feature.

2. GIF or snapshot should be provided if includes UI/interactive modification.

📝 Changelog description

Describe changes from user side, and list all potential break changes or other risks.

1. English description

• Add less variable @pagination-item-bg-active. Make pagination active item background colour parameterized #14739

2. Chinese description (optional)

☑️ 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 56570aa

https://deploy-preview-15302--ant-design.netlify.com

[codecov]

Codecov Report

Merging #15302 into master will increase coverage by 0.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #15302      +/-   ##
==========================================
+ Coverage   94.13%   94.15%   +0.01%     
==========================================
  Files         250      250              
  Lines        6635     6635              
  Branches     1906     1906              
==========================================
+ Hits         6246     6247       +1     
+ Misses        388      387       -1     
  Partials        1        1

Impacted Files	Coverage Δ
components/upload/UploadList.tsx	94.49% <0%> (-1.84%)	⬇️
components/_util/wave.tsx	87.5% <0%> (+2.88%)	⬆️

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