[BUG]: Unable to add user to the `users` group

### Is there an existing issue for this?

- [x] I have searched the existing issues

### Current Behavior

It is currently not possible to add a user to the `users` group.

### Expected Behavior

A `usermod -a -G users ` should work as expected.

### Steps To Reproduce

```
bash-5.1# cat /etc/group | grep users
bash-5.1#
bash-5.1# groupadd -g 100 users
groupadd: group 'users' already exists
bash-5.1# useradd gbraad
bash-5.1# usermod -a -G users gbraad
bash-5.1# groups gbraad
gbraad : gbraad
```

The following workaround is possible:
```
bash-5.1# echo "users:x:100:gbraad" | sudo tee -a /etc/group
users:x:100:gbraad
bash-5.1# groups gbraad
gbraad : gbraad users
```

### Anything else?

This is reported upstream: https://gitlab.com/fedora/bootc/base-images/-/issues/42 as this is also happening for the `fedora-bootc` and `centos-bootc` images.

### Search terms

usermod users useradd