Adjust rollback job configurations

Problem Statement

During the most recent rollback practice, I noticed some jobs which probably do not warrant running. Notably,

• The CNG Verify job in Deployer
• The check stage in k8s-workloads/gitlab-com

Reference: gitlab-org/release/tasks#5119 (comment 1317452735)

Resolution

Evaluate each of these jobs and determine if they serve any benefit to be run during rollbacks at all. If not, let's nix them. Doing so will reduce the amount of jobs run and lessen the chance of a failure negative impacting our ability to execute rollbacks.

Milestones

• Evaluate each of the identified jobs
• Remove or remark why a job may or may not be needed