JSON export contains IPv6 addresses when -ipv4 is provided as a launch argument

[UFeindschiff]

Less of a bug, but more of a suggestion for an improvement, but the assumption when providing -ipv4 as a launch argument is that the results will only contain IPv4 addresses.

Maybe do the check for IPv4/v6 when extracting the output from the graph rather than have it as a filter when displaying the output (as it's seemingly currently done that way for output to textfile and stdout)