[Error] polkit installation fails in opensuse image

## Describe the bug

Installation of the `polkit` package fails in distrobox with the `opensuse/distrobox:latest` and `opensuse/tumbleweed:latest` images.

This happens **only in distrobox**; installation of polkit in a regular `opensuse/tumbleweed:latest` or `opensuse/distrobox:latest` podman container works normally. That's why I am reporting it here rather than on openSUSE bugzilla.

## Steps to reproduce

OpenSUSE MicroOS 20260304
distrobox-1.8.2.4-2.1 on openSUSE MicroOS

```
> distrobox create --image registry.opensuse.org/opensuse/distrobox:latest test
> distrobox enter test
📦[martin@test Distrobox]$ sudo zypper in polkit
(1/4) Installing: libpolkit-agent-1-0-127-2.2.x86_64 ....[done]
(2/4) Installing: libpolkit-gobject-1-0-127-2.2.x86_64 ..[done]
/usr/bin/systemd-sysusers --replace=/usr/lib/sysusers.d/polkitd.conf -
Creating group 'systemd-journal' with GID 494.
Creating group 'polkitd' with GID 493.
Creating user 'polkitd' (User for polkitd) with UID 493 and GID 493.
Creating group 'systemd-coredump' with GID 492.
Creating user 'systemd-coredump' (systemd Core Dumper) with UID 492 and GID 492.
Failed to add existing group "tty" to temporary group file: Invalid argument
error: %prein(polkit-127-2.2.x86_64) scriptlet failed, exit status 1
error: polkit-127-2.2.x86_64: install failed
```

The same happens with `opensuse/tumbleweed:latest`. It also happens if I use a rootful distrobox container.

## Expected behavior

polkit installation works.

## Logs

[distrobox.log.gz](https://github.com/user-attachments/files/25864595/distrobox.log.gz)

## Desktop

distrobox-1.8.2.4-2.1 installed from openSUSE package
OpenSUSE MicroOS 20260304
podman-5.8.0-1.1.x86_64
conmon-2.2.1-1.1.x86_64
runc-1.4.0-1.2.x86_64
crun-1.26-1.2.x86_64

錯誤發生在 polkit 套件的預安裝指令碼中，此時 systemd-sysusers 嘗試建立群組。調查 distrobox 的容器初始化流程，尤其是使用者/群組對映，以及如何呼叫 systemd-sysusers。檢查 distrobox 的 entrypoint 指令碼，並將其環境與一般的 podman 容器進行比較。在本機重現問題，以了解與「tty」群組的衝突。

由索引模型根據 Issue 內容生成。