revert: removing type-guards which use Zod parsing (PL-753)

[zhihil]

…e reliable runtime validation (PL-753) (#790)" (#806)"

This reverts commit b495d0e5271c0379283cb24253e6de90e1e72743.

Fixes or implements PL-753

Brief description. What is this change?

Implementation details. How do you make this change?

Setup information

Deployment Notes

Related PRs

• https://github.com/voiceflow/XXXXXXXXX/pull/123

Checklist

• [ ] Breaking changes have been communicated, including:
  • New required environment variables
  • Renaming of interfaces (API routes, request/response interface, etc)
• [ ] New environment variables have been deployed
• [ ] Appropriate tests have been written
  • Bug fixes are accompanied by an updated or new test
  • New features are accompanied by a new test