k3s.tests: fix eval (#412756)

Author: marcusramberg

nixos/tests/k3s/default.nix

@@ -8,7 +8,7 @@ let
     n: _: lib.strings.hasPrefix "k3s_" n && (builtins.tryEval pkgs.${n}).success
   ) pkgs;
 in
-lib.recurseIntoAttrs {
+{
   airgap-images = lib.mapAttrs (
     _: k3s: import ./airgap-images.nix { inherit system pkgs k3s; }
   ) allK3s;