Update Checkbox component s square size from 16px to 14px (#2686)

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## Related Issue

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<!-- Fixes #0000 -->

## Summary

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- #2684 에서 추가한 Checkbox s
사이즈의 크기가 잘못된 부분을 수정합니다.

## Details
- margin 1px을 포함한 전체 사이즈가 16px인데 내부 square 사이즈를 16px로 잘못 작성했습니다.
- margin을 제외하고 내부 square를 14px로 올바르게 수정합니다.
- [추가된 Checkbox 피그마
컴포넌트](https://www.figma.com/design/99k33ZxchcPKTz2tzJlZeE/Components?node-id=1307-312&m=dev)
<img width="1014" height="428" alt="스크린샷 2025-08-27 오후 6 01 22"
src="https://github.com/user-attachments/assets/389d7cb4-ce63-4f83-906c-7dc82e304d0c"
/>

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### Breaking change? (Yes/No)

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- No
## References

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<!-- This is an auto-generated comment: release notes by coderabbit.ai
-->

## Summary by CodeRabbit

- 스타일
- s 사이즈 체크박스의 정사각형 크기를 16px에서 14px로 축소했습니다. 더 컴팩트한 UI로 폼과 리스트에서 공간 활용이
개선되고 시각적 균형이 향상됩니다.

- 작업(Chores)
  - @channel.io/bezier-react 패키지에 대한 패치 릴리스를 위한 변경 이력을 추가했습니다.

<!-- end of auto-generated comment: release notes by coderabbit.ai -->

Author: annie1229

.changeset/salty-tools-fail.md

@@ -0,0 +1,5 @@
+---
+'@channel.io/bezier-react': patch
+---
+
+Update Checkbox component s square size from 16px to 14px

packages/bezier-react/src/components/Checkbox/Checkbox.module.scss

@@ -37,7 +37,7 @@
     border-radius: 4.6px;
 
     /* stylelint-disable-next-line order/order */
-    @include dimension.square(16px);
+    @include dimension.square(14px);
   }
 
   &:where(.size-m) {