[Terraform] Prevent user processes from killing on SSH disconnect

[adarshxs]

tmux got killed, after SSH disconnection. This should fix it for instances created via terraform

[drbh]

following up on this PR, is this change still needed?

tmux should survive SSH disconnect by default, and this config doesn’t appear to set KillUserProcesses=true or anything else that would explain tmux being killed.

additionally im not sure if this change would resolve the issue anyway, since its setting linger to be on for the root user, and I believe the default user is nixos? lastly if we do want to enable linger I think we may want to set it in the config like users.users.nixos.linger = true;

@adarshxs let me know what your thoughts are. just trying to close/clean up stale PRs.

Thanks!