fix(docs): add iframe sandbox property as else COOP errors occur

[chocolateimage]

🔗 Linked issue

Resolves #987

❓ Type of change

• 📖 Documentation (updates to the documentation or readme)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality)
• ✨ New feature (a non-breaking change that adds functionality)
• 🧹 Chore (updates to the build process or auxiliary tools and libraries)
• ⚠️ Breaking change (fix or feature that would cause existing functionality to change)

📚 Description

The COOP blocks clicking on "Open in Stackblitz" on the pages.

[netlify]

👷 Deploy request for nuxt-tailwindcss pending review.

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Name	Link
🔨 Latest commit	24c100a

[what-the-diff]

PR Summary

• Enhanced Management of Popups within iframes
  We've updated a setting within Sandbox file so our website can now better control and manage any popups. This will lead to improved user experience and website performance.