Woodpecker wasn't able to deploy, because 'result' from a Nix flake is a
symlink to the Nix store, which isn't copied over to a non-Nix
deployment container like plugin-codeberg-pages-deploy. Trying to
troubleshoot deploy steps in particular is hard because, not only do you
not want to have the test stage doing random deployments, but Woodpecker
CLI also features a nice bug where the use of `from_secret` actually
causes the entire pipeline to not run.
Anyway, remove excess permissions that are no longer needed, create a
proper copy step, and fix the deployment.