fix(k8s): point OTEL endpoint to k8s-monitoring-alloy service (#839)

The receiver suffix was stale — the `grafana-k8s-monitoring` module deploys a single Service named `k8s-monitoring-alloy` in the `monitoring` namespace, not `k8s-monitoring-alloy-receiver`. Pods were failing to ship traces with:

```
dial tcp: lookup k8s-monitoring-alloy-receiver.monitoring.svc.cluster.local on 100.64.0.10:53: no such host
```

Drop the `-receiver` suffix so the OTLP exporter resolves the correct service.

Reviewed-on: #839

k8s/deploy.yaml

@@ -67,7 +67,7 @@ spec:
           containerPort: 8080
         env:
         - name: OTEL_EXPORTER_OTLP_ENDPOINT
-          value: http://k8s-monitoring-alloy-receiver.monitoring.svc.cluster.local:4318
+          value: http://k8s-monitoring-alloy.monitoring.svc.cluster.local:4318
         envFrom:
         - configMapRef:
             name: schemas