[kcm/autostart] Fix loading and adding logout scripts
m_xdgConfigPath.filePath(QStringLiteral("/plasma-workspace/shutdown/")) resolves to /plasma-workspace/shutdown/
Remove the leading slash to make it work properly
m_xdgConfigPath.filePath(QStringLiteral("/plasma-workspace/shutdown/")) resolves to /plasma-workspace/shutdown/
Remove the leading slash to make it work properly