reverts the changes from ec64eebfd6
it brakes the flake eval process and other things ?,
setting 'allow-import-from-derivation' doesn't seem like a good fix to me and doesn't work in all cases.
I couldn't find any other solution to fix it for now.
Do this to be in line with other places, where resources get fetched
using git and to hopefully avoid errors such as:
Cannot find Git revision 'da9d3ead9d97ce0fef7538638326264957e2f1b4' in ref 'trunk' of repository 'ssh://forgejo@git.hamburg.ccc.de/CCCHH/infrastructure-authorized-keys.git'! Please make sure that the rev exists on the ref you've specified or add allRefs = true; to fetchGit.
This issue was discovered while trying to make the new hydra work.