fix(module:tree-select): selector cannot focus

[hsuanxyz]

close #6063

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?

[ ] 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: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[ ] No

Other information

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #6073 (8689f10) into master (3204927) will decrease coverage by 0.07%.
The diff coverage is 65.21%.

@@            Coverage Diff             @@
##           master    #6073      +/-   ##
==========================================
- Coverage   89.89%   89.82%   -0.08%     
==========================================
  Files         465      465              
  Lines       14057    14078      +21     
  Branches     2311     2315       +4     
==========================================
+ Hits        12636    12645       +9     
- Misses        873      882       +9     
- Partials      548      551       +3     

Impacted Files	Coverage Δ
components/tree-select/tree-select.component.ts	90.13% <65.21%> (-3.43%)	⬇️
components/table/src/table-data.service.ts	78.46% <0.00%> (-6.16%)	⬇️
components/time-picker/time-holder.ts	95.78% <0.00%> (+1.05%)	⬆️

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