feat(module: input-item): fix input-item bug

[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?

[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: N/A

What is the new behavior?

Does this PR introduce a breaking change?

[ ] Yes
[x] No

Other information

[codecov]

Codecov Report

Merging #500 into master will decrease coverage by 0.02%.
The diff coverage is 33.33%.

@@            Coverage Diff             @@
##           master     #500      +/-   ##
==========================================
- Coverage   87.53%   87.51%   -0.03%     
==========================================
  Files         270      270              
  Lines        7588     7583       -5     
  Branches     1085     1083       -2     
==========================================
- Hits         6642     6636       -6     
- Misses        530      531       +1     
  Partials      416      416

Impacted Files	Coverage Δ
components/input-item/input-item.component.ts	93.96% <33.33%> (-0.64%)	⬇️

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[3fuyu]

#465

[3fuyu]

#496