Required metadata field not detected as incomplete when becoming required after dataset creation

Bug description

Context: This issue is related to #11900 and concerns Scenario 2 identified during testing.

When a controlledVocabulary metadata field becomes required after a dataset has been created (for example, following a metadata block modification via TSV file), Dataverse does not correctly detect this missing metadata.

Issue: The dataset that was previously valid with optional metadata allows form validation even though the newly required field is not filled in.

Steps to reproduce

1. Create a dataset with a set of required metadata
2. Modify the metadata block to make a previously optional field required (e.g., publicationRelationType)
3. Open the existing dataset's edit form
4. Notice that the newly required field is not marked as invalid and the form can be validated without filling in this field

Expected behavior

• The edit form should clearly indicate newly required but unfilled fields
• DRAFT form validation should be blocked until all required fields are filled in

Affected version

Dataverse v6.9

Are you thinking about creating a pull request for this issue?

No fix is currently planned by the team.

Reproduce the issue by changing a metadata block so publicationRelationType becomes required, then open the existing dataset's edit form. Trace the DRAFT form validation for controlledVocabulary fields and verify that newly required, empty fields are marked invalid and block validation.