Update QA E2E documentation

What does this MR do?

Update documentation to reflect the changes necessary from https://gitlab.com/gitlab-org/quality/team-tasks/-/issues/550

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