chore(helm): update image ghcr.io/linuxserver/grav digest to 78915c5 (#32529)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
|
[ghcr.io/linuxserver/grav](https://redirect.github.com/linuxserver/docker-grav/packages)
([source](https://redirect.github.com/linuxserver/docker-grav)) | digest
| `5cc5a27` -> `78915c5` |

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charts/stable/grav/Chart.yaml

@@ -36,4 +36,4 @@ sources:
   - https://github.com/linuxserver/docker-grav
   - https://github.com/truecharts/charts/tree/master/charts/stable/grav
 type: application
-version: 13.5.4
+version: 13.5.5

charts/stable/grav/values.yaml

@@ -1,7 +1,7 @@
 image:
   repository: ghcr.io/linuxserver/grav
   pullPolicy: IfNotPresent
-  tag: 1.7.48@sha256:5cc5a27b5428a60541221f3011911541b4dbff6ad4b6809d55f7bde15b715ced
+  tag: 1.7.48@sha256:78915c57a7afa4972d42e3565c6f01c19a6d6ef97bb81adeb67121064d4e0fc5
 service:
   main:
     ports: