Allow pushing service environment variables via python sdk even if the service does not exist

Hi!

I want to provision new devices via python sdk. Adding devices works, but pushing some service environment variables via
balena.models.device.env_var.set()

only works if the service exists.

Let’s say there has not been pushed a release so far, or the current app releases do not contain a service where I want to add an environment variable to, the call fails.

It would be nice if there is an option to “force” the setting of the variable.

As i remember, the other way round works. If a service is removed the variable is marked as “not used” in balenaCloud.