chore(helm): update image docker.io/grafana/grafana-image-renderer digest to 791977d (#30931)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
| docker.io/grafana/grafana-image-renderer | digest | `9742352` ->
`791977d` |

---

> [!WARNING]
> Some dependencies could not be looked up. Check the Dependency
Dashboard for more information.

Add the preset `:preserveSemverRanges` to your config if you don't want
to pin your dependencies.

---

### Configuration

📅 **Schedule**: Branch creation - At any time (no schedule defined),
Automerge - At any time (no schedule defined).

🚦 **Automerge**: Enabled.

♻ **Rebasing**: Whenever PR becomes conflicted, or you tick the
rebase/retry checkbox.

🔕 **Ignore**: Close this PR and you won't be reminded about this update
again.

---

- [ ] <!-- rebase-check -->If you want to rebase/retry this PR, check
this box

---

This PR has been generated by [Renovate
Bot](https://redirect.github.com/renovatebot/renovate).

<!--renovate-debug:eyJjcmVhdGVkSW5WZXIiOiIzOS44Ni4xIiwidXBkYXRlZEluVmVyIjoiMzkuODYuMSIsInRhcmdldEJyYW5jaCI6Im1hc3RlciIsImxhYmVscyI6WyJhdXRvbWVyZ2UiLCJyZW5vdmF0ZS9jb250YWluZXIiLCJ0eXBlL2RpZ2VzdCJdfQ==-->

charts/stable/grafana-image-renderer/Chart.yaml

@@ -33,4 +33,4 @@ sources:
   - https://github.com/truecharts/charts/tree/master/charts/stable/grafana-image-renderer
   - https://hub.docker.com/r/grafana/grafana-image-renderer
 type: application
-version: 7.4.0
+version: 7.4.1

charts/stable/grafana-image-renderer/values.yaml

@@ -1,7 +1,7 @@
 image:
   pullPolicy: IfNotPresent
   repository: docker.io/grafana/grafana-image-renderer
-  tag: latest@sha256:9742352e362078231f3c33611a774325cc607adda685f7c39fd7ed56527d0f5d
+  tag: latest@sha256:791977d55b7386437ba06082b1d934dbce421549f8dadd3a29849c502a5d36a9
 persistence: {}
 portal:
   open: