Add testcase association to pages_pipeline_spec.rb

What does this MR do?

Per GitLab best practice, tests should be associated with a testcase issue. This associates the pages_pipeline_spec.rb smoke test with the corresponding issue

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