fix(module:input-number): make sure the displayed value is correct

[HyperLife1119]

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: #9309

What is the new behavior?

Does this PR introduce a breaking change?

• Yes
• No

Other information

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 92.12%. Comparing base (d3bc0ee) to head (228a2ae).
⚠️ Report is 3 commits behind head on master.

Additional details and impacted files

@@           Coverage Diff           @@
##           master    #9312   +/-   ##
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  Coverage   92.12%   92.12%           
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  Files         561      561           
  Lines       19627    19631    +4     
  Branches     3106     3107    +1     
=======================================
+ Hits        18082    18086    +4     
  Misses       1206     1206           
  Partials      339      339           

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[HyperLife1119]

关键修复：在输入 1abc 这样的值时，输入前的显示值为 1，输入结束后又经过 parseFloat 将 1abc 格式化为了正确的值 1，导致输入前和输入后的值是一样的，angular 会忽略这个渲染更新。

[Copilot]

Pull Request Overview

This PR fixes a bug in the input-number component to ensure the displayed value is correct during user input. The fix addresses an issue where the display value wasn't properly updated when users typed invalid characters or incomplete numbers.

• Moves the display value update to occur immediately when typing begins
• Conditionally applies formatting only when a formatter is provided during typing
• Improves the default parser to handle empty strings correctly

Reviewed Changes

Copilot reviewed 3 out of 3 changed files in this pull request and generated 2 comments.

File	Description
components/input-number/input-number.component.ts	Updates display value logic and improves default parser for empty strings
components/input-number/input-number.component.spec.ts	Adds test case for invalid input handling
components/input-number/demo/formatter.ts	Updates parser functions to use unary plus operator instead of parseFloat

[Nicoss54]

LGTM

[Laffery]

LGTM