e2e API tests for Group CRUD operations

What does this MR do?

Adds e2e blackbox API test coverage for Groups CRUD operations

What are the relevant issue numbers?

#51026

Does this MR meet the acceptance criteria?

• Changelog entry added, if necessary
• Documentation created/updated
• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the [merge request performance guidelines](https://docs.gitlab.com/ee/development/merge_request_performance_guidelines.html)
• Conforms to the style guides
• Conforms to the database guides