Update single spec syntax to use specify

What does this MR do?

This refactors tests to use specify for the self-explanatory one-liners in GraphQL specs (https://docs.gitlab.com/ee/development/testing_guide/best_practices.html#general-guidelines).

Does this MR meet the acceptance criteria?

Conformity

• Changelog entry
• Documentation (if required)
• Code review guidelines
• Merge request performance guidelines
• Style guides
• Database guides
• Separation of EE specific content