When control plane advertises wrong management port subsequent calls from dashboard should result in errors

[manuranga]

Let's say two control planes running in the same machine, called A and B.
B wrongly advertises the A's management port (via a wrong mgtApiUrl in Config.toml) to the Dashboard.
The dashboard then showed B's name under A's services.
This can't shouldn't ideally happen, since Dashboard's call to get service information should be rejected by B looking at JWT.

But currently, JWT is only used to correlate/validate details calls, not the heartbeat.

Observed by @LakshanWeerasinghe