fix(helm): Gateway Ingester endpoints points to inexistent service when zone aware replication is enabled

[paulojmdias]

What this PR does / why we need it:

When .Values.ingester.zoneAwareReplication.enabled is true, the default service is not created; instead, 1 service per zone. So, in this case, the gateway nginx is trying to reach a service which don't exist for ingester paths.

2025/04/21 14:50:06 [error] 11#11: *4813767 loki-ingester.logging.svc.cluster.local could not be resolved (3: Host not found), client: 1.2.3.4, server: , request: "GET /config HTTP/1.1", host: "loki.dummydomain.com:3100"
{"timestamp":"21/Apr/2025:14:50:06 +0000","remote_addr":"1.2.3.4","remote_user":"admin","request":"GET /config HTTP/1.1","status":502,"body_bytes_sent":559,"http_referer":"","http_user_agent":"Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/135.0.0.0 Safari/537.36","http_x_forwarded_for":""}

Special notes for your reviewer:

Checklist

• Reviewed the CONTRIBUTING.md guide (required)
• Documentation added
• Title matches the required conventional commits format, see here
  • Note that Promtail is considered to be feature complete, and future development for logs collection will be in Grafana Alloy. As such, feat PRs are unlikely to be accepted unless a case can be made for the feature actually being a bug fix to existing behavior.