Upgrade GraphQL gem to 1.8.17 for EE

What does this MR do?

This is the EE version of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/32299

Next step on the way to upgrading to 1.9.x (https://gitlab.com/gitlab-org/gitlab-ce/issues/62535)

This brings the gem to the highest 1.8.x version, 1.8.17

Several changes were required, including needing to use the new BatchLoader::GraphQL.for from batch-loader, (for more details )

Screenshots

Does this MR meet the acceptance criteria?

Conformity

• [-] Changelog entry
• [-] Documentation created/updated or follow-up review issue created
• Code review guidelines
• Merge request performance guidelines
• Style guides
• [-] Database guides
• Separation of EE specific content

Performance and Testing

• Review and add/update tests for this feature/bug. Consider all test levels. See the Test Planning Process.
• [-] Tested in all supported browsers