Client error when a project is deleted in the interface

[wperron]

During the refresh phase of Terraform, if a project was deleted in the interface, it is expected that the provider will remove it from the state as well. Instead the client SDK returns an error because the project wasn't found.

I'll have to compare with other providers for different platforms to see if there's a convention on how to handle these errors but it's clear that it shouldn't stop the plan/apply and instead handle it gracefully.