Optimize CosineSimiliarity

[mejai1206]

🙏 Describe the pull request

CosineSimiliarity를 최적화하였습니다. Linear의 가독성을 개선했습니다.

💬 Additional context

CosineSimiliarity

After

Before

✅ Checklist

• [x] Code follows the project's coding conventions and style.
• [x] Tests have been added or updated to cover the changes.
• [x] Documentation has been updated, if necessary.