fix(users): update mutableUsers to true

Set mutableUsers to true to allow for user configuration changes.

hosts/common/nixos/users/jeff/default.nix

@@ -5,7 +5,7 @@
 }: let
   ifTheyExist = groups: builtins.filter (group: builtins.hasAttr group config.users.groups) groups;
 in {
-  users.mutableUsers = false;
+  users.mutableUsers = true;
   users.users.jeff = {
     isNormalUser = true;
     shell = pkgs.fish;