Revert "Canary toggle compatible with next.gitlab.com"

What does this MR do and why?

Reverts !78936 (merged), accounting for changes made in !79383 (merged).

After discussion in gitlab-com/gl-infra/delivery#2188 (comment 836167977), it was determined that the best course of action for now was to revert this change.

MR acceptance checklist

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

• I have evaluated the MR acceptance checklist for this MR.