fix: 修复 form 数字字符串长度校验错误问题

[honkinglin]

🤔 这个 PR 的性质是？

• 日常 bug 修复
• 新特性提交
• 文档改进
• 演示代码改进
• 组件样式/交互改进
• CI/CD 改进
• 重构
• 代码风格优化
• 测试用例
• 分支合并
• 其他

🔗 相关 Issue

💡 需求背景和解决方案

📝 更新日志

• fix(Form): 修复 form 数字字符串长度校验错误问题

• 本条 PR 不需要纳入 Changelog

☑️ 请求合并前的自查清单

⚠️ 请自检并全部勾选全部选项。⚠️

• 文档已补充或无须补充
• 代码演示已提供或无须提供
• TypeScript 定义已补充或无须补充
• Changelog 已提供或无须提供

[github-actions]

[codecov-commenter]

Codecov Report

Merging #1129 (ee977d5) into develop (f5430d5) will decrease coverage by 0.00%.
The diff coverage is 59.17%.

@@             Coverage Diff             @@
##           develop    #1129      +/-   ##
===========================================
- Coverage    60.29%   60.28%   -0.01%     
===========================================
  Files          955      957       +2     
  Lines        16781    16933     +152     
  Branches      3845     3876      +31     
===========================================
+ Hits         10118    10208      +90     
- Misses        6663     6725      +62     

Impacted Files	Coverage Δ
src/card/_example/base.jsx	100.00% <ø> (ø)
src/card/_example/bordered-none.jsx	75.00% <ø> (ø)
src/card/_example/footer-content-actions.jsx	80.00% <ø> (ø)
src/card/_example/footer.jsx	100.00% <ø> (ø)
src/card/_example/header-all-props.jsx	100.00% <ø> (ø)
src/card/_example/header-bordered.jsx	75.00% <ø> (ø)
src/card/_example/header-description.jsx	100.00% <ø> (ø)
src/card/_example/header-footer-actions.jsx	80.00% <ø> (ø)
...c/card/_example/header-subtitle-footer-actions.jsx	80.00% <ø> (ø)
src/card/_example/header-subtitle.jsx	100.00% <ø> (ø)
... and 44 more

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