System stats warnings when running operating system packages

## Description

I see the following warnings in the Graylog log when using the operating system packages. I have two Docker containers running on the same node.

```
2023-11-14T08:53:02.205Z WARN [LinuxFileSystem] Failed to get information to use statvfs. path: /var/lib/docker/overlay2/608072031f13b3a360c5e65c46c64a17439e56f5edbb7752b13de2cd00bfad6d/merged, Error code: 13
2023-11-14T08:53:02.206Z WARN [LinuxFileSystem] Failed to get information to use statvfs. path: /var/lib/docker/overlay2/1e1ae2a7423529187ab9762628ae9d449c6c149786c1ce517c1f8156f4f0b410/merged, Error code: 13
2023-11-14T08:53:02.212Z WARN [LinuxFileSystem] Failed to get information to use statvfs. path: /var/lib/docker/overlay2/608072031f13b3a360c5e65c46c64a17439e56f5edbb7752b13de2cd00bfad6d/merged, Error code: 13
2023-11-14T08:53:02.213Z WARN [LinuxFileSystem] Failed to get information to use statvfs. path: /var/lib/docker/overlay2/1e1ae2a7423529187ab9762628ae9d449c6c149786c1ce517c1f8156f4f0b410/merged, Error code: 13
2023-11-14T08:53:02.222Z WARN [LinuxFileSystem] Failed to get information to use statvfs. path: /var/lib/docker/overlay2/608072031f13b3a360c5e65c46c64a17439e56f5edbb7752b13de2cd00bfad6d/merged, Error code: 13
2023-11-14T08:53:02.222Z WARN [LinuxFileSystem] Failed to get information to use statvfs. path: /var/lib/docker/overlay2/1e1ae2a7423529187ab9762628ae9d449c6c149786c1ce517c1f8156f4f0b410/merged, Error code: 13
2023-11-14T08:53:02.228Z WARN [LinuxFileSystem] Failed to get information to use statvfs. path: /var/lib/docker/overlay2/608072031f13b3a360c5e65c46c64a17439e56f5edbb7752b13de2cd00bfad6d/merged, Error code: 13
2023-11-14T08:53:02.228Z WARN [LinuxFileSystem] Failed to get information to use statvfs. path: /var/lib/docker/overlay2/1e1ae2a7423529187ab9762628ae9d449c6c149786c1ce517c1f8156f4f0b410/merged, Error code: 13
```

## Steps to Reproduce (for bugs)

1. Run Graylog with operating system packages
2. Install Docker and start a container
3. Observe Graylog warnings in the logs during startup/shutdown

## Context

Graylog runs as an unprivileged user when using the operating system packages.

## Your Environment

* Graylog Version: 5.2.0