feat: resolve #20728 customize header checkbox labels in Transfer

[morenyang]

🤔 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

close #20728

💡 Background and solution

• Add a new prop: selectAllLabels

export type SelectAllLabel =
  | React.ReactNode
  | ((info: { selectedCount: number; totalCount: number }) => React.ReactNode);

export interface TransferProps {
  // ...
  selectAllLabels?: SelectAllLabel[];
}

• Render checkbox label if use provide content or rendering function.

if (selectAllLabel) {
  return typeof selectAllLabel === 'function'
    ? selectAllLabel({ selectedCount, totalCount })
    : selectAllLabel;
}

📝 Changelog

Language	Changelog
🇺🇸 English	Add selectAllLabels prop in Transfer component, allow users to customize header checkbox labels in Transfer.
🇨🇳 Chinese

☑️ 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/transfer/index.en-US.md
View rendered components/transfer/index.zh-CN.md

[tests-checker]

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

[ant-design-bot]

[codesandbox-ci]

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[codecov]

Codecov Report

Merging #21139 into feature will increase coverage by <.01%.
The diff coverage is 100%.

@@             Coverage Diff             @@
##           feature   #21139      +/-   ##
===========================================
+ Coverage    97.45%   97.45%   +<.01%     
===========================================
  Files          296      296              
  Lines         6912     6920       +8     
  Branches      1918     1912       -6     
===========================================
+ Hits          6736     6744       +8     
  Misses         176      176

Impacted Files	Coverage Δ
components/transfer/list.tsx	100% <100%> (ø)	⬆️
components/transfer/index.tsx	95.52% <100%> (+0.03%)	⬆️

---

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[zombieJ]

• checkboxLabel => selectAllLabels
• Add .md demo for this and mark as debug

[morenyang]

• Add .md demo for this and mark as debug

Should I change the base branch to master?

[yoyo837]

• Add .md demo for this and mark as debug

Should I change the base branch to master?

No, continue adding demo in current branch.

[zombieJ]

LGTM
cc @afc163 @yoyo837 @shaodahong