(3.9.0-current) Cluster creation fails on Rocky 9.4

## Issue description

When using a custom AMI based on Rocky 9.4, the cluster creation will fail because the Munge service fails to start with an error message like the one below:

```
munged: Error: Keyfile is insecure: group-writable permissions without sticky bit set on "/etc"
```

This is caused by a [known issue in Rocky 9.4](https://forums.rockylinux.org/t/changed-permissions-on-etc-in-rl9-4-genericcloud-image/14449) vanilla AMI where the permissions of the folder `/etc` have been changed from `0755` to `0777`.

## Affected versions (OSes, schedulers)

All versions of ParallelCluster 3.9.x and later using Rocky 9.4 are impacted.

## Mitigation

You can find a detailed explanation and the mitigation of the problem [here](https://github.com/aws/aws-parallelcluster/wiki/(3.9.0%E2%80%90current)-Cluster-creation-fails-on-Rocky-9.4)

No repository file or test is identified in the issue. Start by locating the cluster-creation path that starts Munge, compare its handling of /etc permissions with the linked Rocky 9.4 mitigation, and define done as successful Rocky 9.4 cluster creation without the Munge keyfile error.

Written by the indexing model from the issue text.