Decommission redis-registry-cache sentinel

Since we are done migrating the registry cache sentinel to redis-cluster-registry for all container registry workloads, we now need to decommission the redis-registry-cache sentinel in pre, gstg, and gprd.

Current monitoring of redis-registry-cache:

Acceptance criteria:

Removing redis-registry-cache from:

• config-mgmt TF (or Tanka Deployment)
• Vault k8s external secrets
• /bin/gkms-vault-edit files
• metrics-catalogue