Monitoring: Clean up blackbox exporter nix expr

nixos/modules/monitoring/exporters/blackbox.nix

@@ -8,15 +8,7 @@
 #
 # Usage: Import this on a monitoring server
 
-{ config, lib, pkgs, ... }:
-
-let
-
-in {
-  # The default limit of 1024 often is too small, see for example
-  # https://github.com/cloudalchemy/ansible-blackbox-exporter/issues/63
-  config.systemd.services.prometheus-blackbox-exporter.serviceConfig.LimitNOFILE = 65000;
-
+{ config, lib, pkgs, ... }: {
   config.services.prometheus.exporters.blackbox = {
     enable = true;