Feat/450 transform for submit

[harshil1793]

Description

This PR includes following changes:

• Flattening checkbox object fields
• Transform the data on submit
• Checkbox Group validation changes

Original issue(s)

department-of-veterans-affairs/va-forms-system-core#450

Testing done

yes

Screenshots

Definition of done

• [ ] Package.json version has been updated to match Github release tag
• [ ] Documentation has been updated, if applicable
• [ ] A link to the original github issue has been provided
• [ ] No sensitive information (i.e. PII/credentials/internal URLs etc.) is captured in logging, hardcoded, or specs

[bjmccotter7192]

Noticed in the branch when I ran yarn build I got some new documents that were generated. Just a heads up to check your build after you merge from main.

[va-vsp-bot]

:tada: This PR is included in version 1.4.0 :tada:

The release is available on GitHub release

Your semantic-release bot :package::rocket: