Clarify that Consul port 8301/TCP needs to be open

What does this MR do?

I was in the process of following the Consul server docs https://docs.gitlab.com/ee/administration/consul.html

Part of this is to ensure the ports necessary for Consul are open on the firewall.

The docs implied that you only need to open port 8301 for UDP. However you need to open port 8301 for both TCP and UDP - see https://developer.hashicorp.com/consul/docs/install/ports

If you don't allow 8301/TCP, the sudo /opt/gitlab/embedded/bin/consul members command won't show the other Consul servers.

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