Track all client connections

[dadgar]

Fixes an issue in which the server could loose a reference to a client even if the client was connected to it. In order for this to happen, the client would connect to a server over address A. Then at some point, heartbeats or Consul discovery, the client's server set is updated to connect via address B. Both of these address would resolve to the same server but the server would clear out the connection first made from connecting via Address A. Eventually address B connection would be closed because it is idle and isn't being used by the client.

Now the state is the client still has a connection via Address A but the server has no reference to the client at all.

Fixes #4203

[github-actions]

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