fixed snapshot for cameras with unused ports

  var total_ports = 0;

  for(var i=0;i<ptrs.length;i++){

    total_ports += $(ptrs[i]).find('port').length;

    let port_counter = 0;

    let ports = $(ptrs[i]).find('port');

    for(p of ports){

        let sensors = $(p).attr("sensor").replace(/\s/g,'').split(",");

        if (!sensors.every(v => v==='none')){

            port_counter++;

        }

    }

    total_ports += port_counter;

  }

  var ts = [];