fix(module:input-number): ngModel value can be undefined

[dev-anton-ko]

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?

Binding of the undefined field cause the error in the log:

core.mjs:6537 ERROR TypeError: Cannot read properties of undefined (reading 'toString') at defaultFormater (ng-zorro-antd-input-number.mjs:313:18) at _NzInputNumberComponent.setValue (ng-zorro-antd-input-number.mjs:468:49) at ng-zorro-antd-input-number.mjs:418:12 at untracked (untracked-BKcld_ew.mjs:573:12) at untracked2 (core.mjs:38350:10) at _NzInputNumberComponent.writeValue (ng-zorro-antd-input-number.mjs:416:5) at onChange (forms.mjs:3476:23) at forms.mjs:3992:42 at Array.forEach (<anonymous>) at FormControl2.setValue (forms.mjs:3992:22)

Issue Number: N/A

What is the new behavior?

No error message.

Does this PR introduce a breaking change?

• Yes
• No

Other information

Just bug has been fixed.
The discussion had been created early #9121
I am not sure that number | null is a proper type for value of this component.

[zorro-bot]

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[codecov]

Codecov Report

All modified and coverable lines are covered by tests ✅

Project coverage is 92.11%. Comparing base (2c7c402) to head (f95ca49).
Report is 4 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9269   +/-   ##
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  Coverage   92.11%   92.11%           
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  Files         561      561           
  Lines       19609    19610    +1     
  Branches     3101     3102    +1     
=======================================
+ Hits        18062    18063    +1     
  Misses       1207     1207           
  Partials      340      340           

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[HyperLife1119]

I think we just need to convert undefined to null in writeValue.

  writeValue(value: number | null | undefined): void {
    if (isNil(value)) value = null;
    untracked(() => {
      this.value.set(value);
      this.setValue(value);
    });
  }

[Laffery]

LGTM