address fish by full patch

otherwise, if another package provides `fish` we are in trouble

Signed-off-by: Harald Hoyer <harald@hoyer.xyz>

modules/nixos/user/default.nix

@@ -74,7 +74,7 @@ in
           cfg.icon;
       };
       extraOptions.programs.bash.initExtra = ''
-        [[ $WANT_BASH ]] || exec env fish -l
+        [[ $WANT_BASH ]] || ${pkgs.fish}/bin/fish -l
       '';
     };