fix(module:modal): nzAutofocus doesn't work correctly

[rorry121]

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: #5319

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #5313 into master will decrease coverage by 0.00%.
The diff coverage is 100.00%.

@@            Coverage Diff             @@
##           master    #5313      +/-   ##
==========================================
- Coverage   91.35%   91.35%   -0.01%     
==========================================
  Files         551      551              
  Lines       13908    13909       +1     
  Branches     2099     2099              
==========================================
  Hits        12706    12706              
  Misses        712      712              
- Partials      490      491       +1     

Impacted Files	Coverage Δ
...ponents/modal/modal-confirm-container.component.ts	100.00% <ø> (ø)
components/modal/modal-footer.component.ts	100.00% <ø> (ø)
components/modal/utils.ts	100.00% <ø> (ø)
components/modal/modal.component.ts	96.73% <100.00%> (+0.03%)	⬆️
components/time-picker/time-holder.ts	94.73% <0.00%> (-1.06%)	⬇️

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[hsuanxyz]

LGTM