prometheus-exporter/unifi-poller: Add loki config

Allows unifi logs to be sent to Loki via unifi-poller

nixos/modules/services/monitoring/prometheus/exporters/unifi-poller.nix

@@ -13,6 +13,7 @@ let
       http_listen = "${cfg.listenAddress}:${toString cfg.port}";
       report_errors = cfg.log.prometheusErrors;
     };
+    inherit (cfg) loki;
   });
 
 in {
@@ -20,6 +21,7 @@ in {
 
   extraOpts = {
     inherit (options.services.unifi-poller.unifi) controllers;
+    inherit (options.services.unifi-poller) loki;
     log = {
       debug = mkEnableOption "debug logging including line numbers, high resolution timestamps, per-device logs.";
       quiet = mkEnableOption "startup and error logs only.";