wireplumber service fails to start in home-pipewire-service-type

Immediately after logging into an account with

home-pipewire-service-type in the home environment, about 5 error

messages appear about the wireplumber service failing and restarting.

Eventually herd gives up trying to start wireplumber.

Trying to start it manually using `herd start wireplumber` results in

the message:

herd: error: failed to start service wireplumber

The other pipewire-related services appear to have started successfully.

home-dbus-service-type is in the home environment also.