Add support to detect if connectivity to interactsh is blocked in order to prevent false nagatives

[forgedhallpass]

Requester: @fail-open

"add a canary component to interactsh that can call out to interactsh server (securely), can point nuclei at that server so it can do a connectivity check to determine if internal systems have outbound access to interactsh. When companies decide to block oob servers it is hard to tell if getting false negatives."

Reference: https://discord.com/channels/695645237418131507/700092442661355602/1007645493028995212

[fail-open]

Thank you for documenting this 😀