fix(module:radio): children unable to focus in radio label

[hsuanxyz]

close #2774

PR Checklist

Please check if your PR fulfills the following requirements:

• The commit message follows our guidelines: https://github.com/NG-ZORRO/ng-zorro-antd/blob/master/CONTRIBUTING.md#commit
• Tests for the changes have been added (for bug fixes / features)
• Docs have been added / updated (for bug fixes / features)

PR Type

What kind of change does this PR introduce?

[x] Bugfix
[ ] Feature
[ ] Code style update (formatting, local variables)
[ ] Refactoring (no functional changes, no api changes)
[ ] Build related changes
[ ] CI related changes
[ ] Documentation content changes
[ ] Application (the showcase website) / infrastructure changes
[ ] Other... Please describe:

What is the current behavior?

Issue Number: #2774

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

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[codecov]

Codecov Report

Merging #2850 into master will decrease coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #2850      +/-   ##
==========================================
- Coverage    95.5%   95.48%   -0.02%     
==========================================
  Files         523      523              
  Lines       12236    12237       +1     
  Branches     1668     1668              
==========================================
- Hits        11686    11685       -1     
- Misses        197      198       +1     
- Partials      353      354       +1

Impacted Files	Coverage Δ
components/radio/nz-radio.component.ts	98.3% <100%> (+0.02%)	⬆️
components/radio/nz-radio-group.component.ts	90% <0%> (-3.34%)	⬇️

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[hejinzhi]

请问大概什么时候能合并，谢谢