fix(module: inputitem): fixed style flash

[sWhite01111]

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-mobile/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

[codecov]

Codecov Report

Merging #377 into master will decrease coverage by 0.05%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master     #377      +/-   ##
==========================================
- Coverage   89.56%   89.51%   -0.06%     
==========================================
  Files         229      229              
  Lines        6892     6894       +2     
  Branches      564      564              
==========================================
- Hits         6173     6171       -2     
- Misses        554      558       +4     
  Partials      165      165

Impacted Files	Coverage Δ
components/input-item/input-item.component.ts	98.4% <100%> (+0.01%)	⬆️
components/picker/picker.service.ts	88.88% <0%> (-5.56%)	⬇️
components/picker/picker.component.ts	80.23% <0%> (-1.75%)	⬇️

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