feat: add bg_BG localisations for form

[tangzixuan]

[中文版模板 / Chinese template]

🤔 This is a ...

• New feature
• 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

#23369

💡 Background and solution

📝 Changelog

Language	Changelog
🇺🇸 English	add bg_BG localisations for form
🇨🇳 Chinese	完善 bg_BG form组件 i18n

☑️ Self-Check before Merge

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

• Doc is updated/provided or not needed
• Demo is updated/provided or not needed
• TypeScript definition is updated/provided or not needed
• Changelog is provided or not needed

---

🚀 Summary

🤖 Generated by Copilot at 408b185

This pull request adds support for Bulgarian locale in the Form component. It creates a new file components/locale/bg_BG.ts with the translations and variables for the error messages and labels.

🔍 Walkthrough

🤖 Generated by Copilot at 408b185

• Add Bulgarian translations for the Form component of the ant-design library (link, link)

• Add a template string for the error message when a field value is not a valid type in components/locale/bg_BG.ts (link)
• Add a nested object with the key Form to the localeValues object in components/locale/bg_BG.ts (link)

[github-actions]

[codecov]

Codecov Report

Patch coverage: 100.00% and no project coverage change.

Comparison is base (7006b37) 100.00% compared to head (408b185) 100.00%.

Additional details and impacted files

@@            Coverage Diff            @@
##            master    #42203   +/-   ##
=========================================
  Coverage   100.00%   100.00%           
=========================================
  Files          617       617           
  Lines        10542     10543    +1     
  Branches      2882      2882           
=========================================
+ Hits         10542     10543    +1     

Impacted Files	Coverage Δ
components/locale/bg_BG.ts	100.00% <100.00%> (ø)

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