Add GitLab Insights e2e tests

What does this MR do?

Add E2E tests for default Gitlab Insights for projects and groups.

gitlab-org/quality/testcases#101 (closed)

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