bug#49613: On WSL1/2, guix install: error: cannot kill processes for uid `999': failed with exit code 1

[Anadon]

Talking with iskarian on IRC, we've confirmed that guix successfully
installs, almost successfully sets up (the init.d isn't set up to actually
daemonize), but for `guix build`, `guix install` and `guix pull` all fail
with "guix <SUB_CMD>: error: cannot kill processes for uid `998': failed
with exit code 1" when using WSL1/2.