[SELC-7462] feat: add parentInstitutionId in user-group APIs

[giulia-tremolada]

List of Changes

• add parentInstitutionId field in:
  • get user group by id API
  • get user groups API
  • create user group API
• modify checkGroupUniqueness logic to block creating groups with same institutionId-parentInstitutionId-productId
• add parentInstitutionId as mongodb index
• add cucumber tests

Motivation and Context

This PR aligns the handling of the parentInstitutionId field, ensuring it is properly persisted both during the creation of a new group and when retrieving existing groups.

How Has This Been Tested?

It was tested locally

Screenshots (if appropriate):

Types of changes

• 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:

• My change requires a change to the documentation.
• I have updated the documentation accordingly.

[sonarqubecloud]

Quality Gate passed

Issues
0 New issues
0 Accepted issues

Measures
0 Security Hotspots
0.0% Coverage on New Code
0.0% Duplication on New Code

See analysis details on SonarQube Cloud