fix(design): fontFamily in nested ConfigProvider should be correct when enable theme.customFont

[dengfuping]

📦 Modified package

• [x] @oceanbase/design
• [ ] @oceanbase/ui
• [ ] @oceanbase/icons
• [ ] @oceanbase/charts
• [ ] @oceanbase/util
• [ ] @oceanbase/codemod
• [ ] Other (about what?)

🤔 This is a ...

• [ ] New feature
• [x] Bug fix
• [ ] Site / documentation update
• [ ] Demo update
• [ ] Component style update
• [ ] TypeScript definition update
• [ ] Bundle size optimization
• [ ] Performance optimization
• [ ] Enhancement feature
• [ ] Internationalization
• [ ] Refactoring
• [ ] Code style optimization
• [ ] Test Case
• [ ] Branch merge
• [ ] Workflow
• [ ] Other (about what?)

🔗 Related issue link

• None

💡 Background and solution

• None

📝 Changelog

Language	Changelog
🇺🇸 English
🇨🇳 Chinese	🐞 修复 ConfigProvider 开启 theme.customFont 并且多次嵌套后 fontFamily 不正确的问题。

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⚠️ Please check all items below before requesting a reviewing. ⚠️

• [x] Doc is updated/provided or not needed
• [x] Demo is updated/provided or not needed
• [x] TypeScript definition is updated/provided or not needed
• [x] Tests is updated/provided or not needed
• [x] Changelog is provided or not needed

[github-actions[bot]]