fix(helm): update chart loki ( 6.6.3 → 6.6.4 ) (#3889)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [loki](https://grafana.github.io/helm-charts)
([source](https://togithub.com/grafana/helm-charts)) | patch | `6.6.3`
-> `6.6.4` |

---

### Release Notes

<details>
<summary>grafana/helm-charts (loki)</summary>

###
[`v6.6.4`](https://togithub.com/grafana/helm-charts/releases/tag/helm-loki-6.6.4)

Helm chart for Grafana Loki and Grafana Enterprise Logs supporting both
simple, scalable and distributed modes.

Source commit:
grafana/loki@05176e4

Tag on source:
https://github.com/grafana/loki/releases/tag/helm-loki-6.6.4

</details>

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Co-authored-by: repo-jeeves[bot] <106431701+repo-jeeves[bot]@users.noreply.github.com>

kubernetes/main/apps/observability/loki/app/helm-release.yaml

@@ -8,7 +8,7 @@ spec:
   chart:
     spec:
       chart: loki
-      version: 6.6.3
+      version: 6.6.4
       sourceRef:
         kind: HelmRepository
         name: grafana-charts