nix3 CLI never honored that setting.
When we update a nix3 profile element with new built store paths for
which we know the deriver (the derivation path which built it), we add
the derivation paths to the profile element to prevent garbage
collection the same way the nix2 CLI logic does.
Fixes#1095.
Change-Id: Icc236d174c5ce5ffe042d1c8e1968f6cb5b50359
Signed-off-by: Raito Bezarius <raito@lix.systems>