refactor(session): remove unnecessary async for clear

[remonke]

🔗 Linked issue

❓ Type of change

• 📖 Documentation (updates to the documentation, readme, or JSdoc annotations)
• 🐞 Bug fix (a non-breaking change that fixes an issue)
• 👌 Enhancement (improving an existing functionality like performance)
• ✨ 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

Removes unnecessary async from the clearSession() function. setCookie is a synchronous function, so the function doesn't have to be asynchronous.

📝 Checklist

• I have linked an issue or discussion.
• I have updated the documentation accordingly.

[pi0]

Thanks for PR. The clearSession / clear utils were intentionally marked as async for future compatibility we might need them async. I've made a refactor to keep it more readable.