Fix spec for routes to the GraphqlController

What does this MR do?

GraphQL route spec was testing the wrong endpoint

Does this MR meet the acceptance criteria?

• Tests added for this feature/bug
• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides (https://about.gitlab.com/handbook/engineering/quality/guidelines/test-engineering/).
• Security reports checked/validated by reviewer