fix(helm-chart): update helm release grafana to 7.3.8 (#458)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| [grafana](https://grafana.com)
([source](https://togithub.com/grafana/helm-charts)) | patch | `7.3.7`
-> `7.3.8` |

---

### Release Notes

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

###
[`v7.3.8`](https://togithub.com/grafana/helm-charts/releases/tag/grafana-7.3.8)

[Compare
Source](https://togithub.com/grafana/helm-charts/compare/grafana-7.3.7...grafana-7.3.8)

The leading tool for querying and visualizing time series and metrics.

#### What's Changed

- \[grafana] Update to version 10.4.1 by
[@&#8203;terop](https://togithub.com/terop) in
[grafana/helm-charts#3039

**Full Changelog**:
grafana/helm-charts@rollout-operator-0.15.0...grafana-7.3.8

</details>

---

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rebase/retry checkbox.

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---

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---

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kubernetes/main/apps/monitoring/grafana/app/helmrelease.yaml

@@ -13,7 +13,7 @@ spec:
         kind: HelmRepository
         name: grafana
         namespace: flux-system
-      version: 7.3.7
+      version: 7.3.8
   interval: 30m
   timeout: 20m
   values: