fix: added checks on unauthorized server actions

[gupta-piyush19]

What does this PR do?

fixes unauthorized server actions

How should this be tested?

• can be tested by mocking the API call with invalid sharing key

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

Appreciated

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

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[github-actions]

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