guix pull: error: cannot kill processes for uid `999': failed with exit code 1

<!-- Describe the bug you encounter below. Please provide the output of the command `guix describe`. --> I'm using GNU Guix on Ubuntu 24.04.4 LTS. Recently `guix pull` started to fail with the following error: ```shell $ guix pull --url="https://codeberg.org/guix/guix" Updating channe...