udevmon loses PATH when invoking jobs

Right now, udevmon invokes jobs by wrapping them with sh -c "..." and then calling execvpe with an empty environment.

A consequence of this is that if you carefully construct a PATH before invoking udevmon, it won't matter: the only commands available to run are the ones that end up in the PATH construct by the sh command. This is the cause of this bug: https://github.com/NixOS/nixpkgs/issues/126681.

I think an easy fix would be to switch from using execvpe to execv. Would that be an acceptable change?

Thanks, Jeremy