Enabling Workspaces on staging

Description

This issue is a change request for enabling Workspaces on staging as part of Release Workspaces HTTP Server in GitLab Agent ... (#27468)

MRs

1. Enabling Workspaces on staging - Enable workspaces on staging (gitlab-com/gl-infra/k8s-workloads/gitlab-com!4754)
2. Adds workspaces support in HAProxy cookbook - Add workspaces (gitlab-cookbooks/gitlab-haproxy!435)
3. Configures HAProxy for Workspaces on staging - https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/merge_requests/6549+
4. Configured Load Balancer for handling Workspaces traffic on staging - https://gitlab.com/gitlab-com/gl-infra/chef-repo/-/merge_requests/6549+