removed map_end_dt column

discord_verificiation/sql/create_tables_playtime_service.sql

@@ -3,7 +3,6 @@ CREATE TABLE `playtime_display_map_history` (
   `map_id` bigint(20) unsigned NOT NULL AUTO_INCREMENT,
   `map_name` varchar(64) NOT NULL,
   `map_start_dt` datetime NOT NULL DEFAULT current_timestamp(),
-  `map_end_dt` datetime DEFAULT NULL,
   PRIMARY KEY (`map_id`),
   KEY `idx_map_name` (`map_name`,`map_start_dt`),
   KEY `idx_start` (`map_start_dt`)