Feature flag: FF_ENABLE_PROJECT_PREFIX_COOKIE_PATH

Summary

This issue is to rollout Add project prefix in session cookie path on production, that is currently behind the FF_ENABLE_PROJECT_PREFIX_COOKIE_PATH feature flag.

Related issue: Tech Eval: Set path variable at cookie level to... (#1088 - closed)

Expectations

What are we expecting to happen?

Session cookie will have path value assigned.

What might happen if this goes wrong?

I might affect user login to private pages projects. In that case, we can revert this MR: !937 (merged)

Rollout Steps

• Temporarily enable with environment variable: gitlab-com/gl-infra/k8s-workloads/gitlab-com!3395 (merged)
• Enable by default (optional): !960 (merged)
• Remove the feature flag: Link to the MR

Rollback Considerations/Events

• Disabling with environment variable: Link to the MR
• Remove the feature flag: Link to the MR