Fixes an issue where passing in customProperties would render invalidly encoded object

[sdglhm]

Description

This fixes an issue where when passing in customProperties to a Choice would lead to render [object Object] instead of properly rendering JSON structure.

Types of changes

• [ ] Chore (tooling change or documentation change)
• [ ] Refactor (non-breaking change which maintains existing functionality)
• [x] Bug fix (non-breaking change which fixes an issue)
• [ ] New feature (non-breaking change which adds functionality)
• [ ] Breaking change (fix or feature that would cause existing functionality to not work as expected)

Checklist

• [x] My code follows the code style of this project.
• [x] I have added new tests for the bug I fixed/the new feature I added.
• [ ] I have modified existing tests for the bug I fixed/the new feature I added.
• [ ] My change requires a change to the documentation.
• [ ] I have updated the documentation accordingly.