fix "contradicting requirement dependencies configured" error

this solves the issue with systemctl --user restart lomiri-full-greeter.service returning the error:

Failed to restart lomiri-full-greeter.service: Transaction contains conflicting jobs 'restart' and 'stop' for lomiri-polkit-agent.service. Probably contradicting requirement dependencies configured.

it appears it is failing because lomiri-polkit-agent is a part of the services that conflict with lomiri-full-greeter