Remove suggested reviewers scenario

What does this MR do and why?

Resolves gitlab-org/quality/quality-engineering/team-tasks#3751 (closed)

Remove suggested reviewers scenario from gitlab-qa as feature is removed https://gitlab.com/groups/gitlab-org/-/epics/14867

Test has been removed in gitlab project with gitlab!189874 (merged)

How to set up and validate locally

Best to use pipeline results from this MR https://gitlab.com/gitlab-org/gitlab-qa/-/pipelines/1890282497

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• Commits include Changelog: trailer
• I have evaluated the MR acceptance checklist for this MR.