feat: add `isCustomField` property to crm properties api

[jatinsandilya]

Description

Add isCustomField property to crm properties api

Type of change

• [x] New feature (non-breaking change which adds functionality)

How Has This Been Tested?

Tested with postman

Checklist:

• [x] My code follows the style guidelines of this project
• [x] I have performed a self-review of my code
• [x] Any dependent changes have been merged and published in downstream modules

[vercel[bot]]

The latest updates on your projects. Learn more about Vercel for Git ↗︎

Name	Status	Preview	Comments	Updated (UTC)
revert-client	✅ Ready (Inspect)	Visit Preview	💬 Add feedback	Mar 15, 2024 11:15am

[github-actions[bot]]

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