fix - null body case

[madmansn0w]

🤔 这个变动的性质是？/ What is the nature of this change?

• 新特性提交 / New feature
• bug 修复 / Fix bug
• 样式优化 / Style optimization
• 代码风格优化 / Code style optimization
• 性能优化 / Performance optimization
• 构建优化 / Build optimization
• 网站、文档、Demo 改进 / Website, documentation, demo improvements
• 重构代码或样式 / Refactor code or style
• 测试相关 / Test related
• 其他 / Other

🔗 相关 Issue / Related Issue

fixes #123

💡 需求背景和解决方案 / Background or solution

Github tasklist issue creation enables users to quickly create blank issues for items in a tasklist. When using check-issue or any other method that utilizes the body-includes filter, an issue with a null body will throw an error.

The solution is to utilize optional chaining - if the property of the object is undefined or null, it will not throw an error.

📝 更新日志 / Changelog

Language	Changelog
🇺🇸 English	Fix null body case which would throw errors when using body-includes
🇨🇳 Chinese

[github-actions]

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