[misc] Add service definition for netbird-signal (#4620)

Author: mlsmaycon

infrastructure_files/docker-compose.yml.tmpl.traefik

@@ -49,6 +49,7 @@ services:
     - traefik.http.routers.netbird-wsproxy-signal.service=netbird-wsproxy-signal
     - traefik.http.services.netbird-wsproxy-signal.loadbalancer.server.port=80
     - traefik.http.routers.netbird-signal.rule=Host(`$NETBIRD_DOMAIN`) && PathPrefix(`/signalexchange.SignalExchange/`)
+    - traefik.http.routers.netbird-signal.service=netbird-signal
     - traefik.http.services.netbird-signal.loadbalancer.server.port=10000
     - traefik.http.services.netbird-signal.loadbalancer.server.scheme=h2c