nextcloud: only use settings when available

modules/nextcloud.nix

@@ -1,4 +1,4 @@
-{ config, lib, libS, pkgs, ... }:
+{ config, lib, libS, options, pkgs, ... }:
 
 let
   cfg = config.services.nextcloud;
@@ -51,7 +51,8 @@ in
           "opcache.jit_buffer_size" = "128M";
         };
 
-        settings = lib.mkMerge [
+        # TODO: drop when 23.11 support is not longer required
+        ${if options.services.nextcloud?settings then "settings" else "extraOptions"} = lib.mkMerge [
           (lib.mkIf cfg.recommendedDefaults {
             # otherwise the Logging App does not function
             log_type = "file";