Cannot start multiple SRT Caller connections using the same remote port number

[voltagectrl]

Creating multiple SRT Caller connections to the same server and port creates a warning in the UI and the settings are not saved correctly preventing the usage of multiple outgoing SRT Calls to the same server/port combination.

This is common practice when sending SRT streams to a CDN-service. All connections are made to the same host and port and the individual streams are identified on the CDN side using the SRT ID-parameter.