Add config option to suppress unknown device type messages

Adds log_unknown_types config option (default: false) to control logging
of unknown UniFi device types. When disabled (default), unknown devices
are silently ignored to reduce log volume. When enabled, they are logged
as DEBUG messages instead of ERROR. Addresses issue #912.

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

pkg/promunifi/collector.go

@@ -452,6 +452,8 @@ func (u *promUnifi) switchExport(r report, v any) {
 	case *unifi.UsageByCountry:
 		u.exportCountryTraffic(r, v)
 	default:
-		u.LogErrorf("invalid type: %T", v)
+		if u.Collector.Poller().LogUnknownTypes {
+			u.LogDebugf("unknown type: %T", v)
+		}
 	}
 }