fix(module:select): display IME input completely

[QichenZhu]

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: #5656

IME input is not displayed in the select box completely.

What is the new behavior?

IME input is displayed in the select box completely.

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

The side effect is that a search is performed every time a key is pressed in IME input mode.

[zorro-bot]

This preview will be available after the AzureCI is passed.

[codecov]

Codecov Report

Merging #5657 into master will not change coverage.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #5657   +/-   ##
=======================================
  Coverage   90.31%   90.31%           
=======================================
  Files         455      455           
  Lines       13788    13788           
  Branches     2258     2181   -77     
=======================================
  Hits        12452    12452           
  Misses        819      819           
  Partials      517      517           

Impacted Files	Coverage Δ
components/select/select-search.component.ts	86.95% <100.00%> (ø)

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[vthinkxie]

lgtm
thanks @QichenZhu

[github-actions]

🎊 PR Preview 111721a has been successfully built and deployed to https://NG-ZORRO-ng-zorro-antd-preview-pr-5657.surge.sh

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