fixup! fix setting default exporter settings

`v.default` always fails because v is the (boolean) attrvalue of the
default settings.

`lib.mkOptionDefault v` would work fine.
But let's just plainly set the default option value.
This way, we can later convert the `settings` option to use
@Atemu's `defaultPriority` (NixOS#296979)
without forcing users to update their config.

nixos/modules/services/misc/paperless.nix

@@ -497,8 +497,7 @@ in
       "d '${cfg.exporter.directory}' - ${cfg.user} ${config.users.users.${cfg.user}.group} - -"
     ];
 
-    services.paperless.exporter.settings =
-      lib.mapAttrs (n: v: lib.mkOptionDefault v.default) options.services.paperless.exporter.settings.default;
+    services.paperless.exporter.settings = options.services.paperless.exporter.settings.default;
 
     systemd.services.paperless-exporter = {
       startAt = lib.defaultTo [] cfg.exporter.onCalendar;

nixos/tests/paperless.nix

@@ -13,7 +13,7 @@ import ./make-test-python.nix ({ lib, ... }: {
           enable = true;
 
           settings = {
-            "no-color" = false; # override a default option
+            "no-color" = lib.mkForce false; # override a default option
             "no-thumbnail" = true; # add a new option
           };