chore(helm): update image docker.io/nginxinc/nginx-unprivileged digest to ad78b4a (#39308)

This PR contains the following updates:

| Package | Update | Change |
|---|---|---|
|
[docker.io/nginxinc/nginx-unprivileged](https://redirect.github.com/nginx/docker-nginx-unprivileged)
| digest | `451ec1d` -> `ad78b4a` |

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charts/premium/nextcloud/values.yaml

@@ -5,7 +5,7 @@ image:
 nginxImage:
   repository: docker.io/nginxinc/nginx-unprivileged
   pullPolicy: IfNotPresent
-  tag: 1.29.1@sha256:451ec1db67978686908d931cc090ac9f6649a5dfbde0d7d3b33756f7c6303f7e
+  tag: 1.29.1@sha256:ad78b4a52a68a93aa3490260e0bf7b3afd35689d312f22bb28300fbe43a158e5
 imaginaryImage:
   repository: oci.trueforge.org/tccr/nextcloud-imaginary
   pullPolicy: IfNotPresent