Handle requests going to replicas with no sentinel running

[MuhammadQadora]

In our deployment the loadbalancer directs sentinel requests to all replicas. This is problematic since we only run 3 sentinels as required by our deployment (node-0, node-1, sentinel-0). If the load balancer redirects to a replica the is not running a sentinel (ex: node-2) the connection will fail.

[dudizimber]

@MuhammadQadora let's remove the add/remove replica tests while we don't allow users to add more replicas