CVE-2026-44933: Path Traversal in Plugin Loading in libzypp

`PluginScript` attempts to `chroot` the plugin to the `repoManagerRoot`, this root is frequently `/` (the system root) in standard configurations or when using `--root`. If the chroot target is `/`, it is a no-op, allowing the traversed path to execute host binaries (like `/bin/bash`) with root privileges.