Make review actions Manual.

What does this MR do?

To temporarily remedy the AWS limiting issues we are having stemming from review apps, let's make review apps on CE manual. (Leave EE automatic)

What are the relevant issue numbers?

• https://gitlab.com/gitlab-com/gl-infra/infrastructure/issues/5738

Does this MR meet the acceptance criteria?

• Conforms to the code review guidelines
• Conforms to the merge request performance guidelines
• Conforms to the style guides
• Conforms to the database guides
• Link to e2e tests MR added if this MR has Requires e2e tests label. See the Test Planning Process.
• Security reports checked/validated by reviewer