removed the addition of client_id to app_config

this field is added automatically and not needed to be added by the update script.

database/3.0.2_to_3.1.0.sql

@@ -320,7 +320,6 @@ INSERT INTO `ospos_app_config` (`key`, `value`) VALUES
 ('barcode_width', '250'),
 ('cash_decimals', '2'),
 ('cash_rounding_code', '0'),
-('client_id', ''),
 ('receiving_calculate_average_price', '0');
 
 -- replace old tokens in ospos_app_config