nixos/galene: do not restrict AF_NETLINK

Built-in TURN server requires AF_NETLINK address family.

nixos/modules/services/web-apps/galene.nix

···
           ProtectSystem = "strict";
           ReadWritePaths = cfg.recordingsDir;
           RemoveIPC = true;
-          RestrictAddressFamilies = [ "AF_INET" "AF_INET6" ];
+          RestrictAddressFamilies = [ "AF_INET" "AF_INET6" "AF_NETLINK" ];
           RestrictNamespaces = true;
           RestrictRealtime = true;
           RestrictSUIDSGID = true;