fix: use localized question headline when extracting survey details

[gcascio]

What does this PR do?

Currently the question headers in exported response files (CSV and Excel) are displayed as [object Object]. The reason is that the headlines of questions are used directly in a string template although they are records.

How should this be tested?

• Add at least one question to a survey and then export the responses as CSV or Excel

Checklist

Required

• Filled out the "How to test" section in this PR
• Read How we Code at Formbricks
• Self-reviewed my own code
• Commented on my code in hard-to-understand bits
• Ran pnpm build
• Checked for warnings, there are none
• Removed all console.logs
• Merged the latest changes from main onto my branch with git pull origin main
• My changes don't cause any responsiveness issues
• First PR at Formbricks? Please sign the CLA! Without it we wont be able to merge it 🙏

Appreciated

• If a UI change was made: Added a screen recording or screenshots to this PR
• Updated the Formbricks Docs if changes were necessary

[vercel]

@gcascio is attempting to deploy a commit to the formbricks Team on Vercel.

A member of the Team first needs to authorize it.

[github-actions]

Thank you for following the naming conventions for pull request titles! 🙏

[mattinannt]

@gcascio thanks a lot for this fix! 🚀💪 Looks great! :-)