Unify MySQL configuration (#12644)

### What problem does this PR solve?

Align MySQL defaults between docker/.env and
docker/service_conf.yaml.template
close #12645

### Type of change

- [x] Other (please describe):Unify MySQL configuration

docker/docker-compose-base.yml

@@ -188,7 +188,7 @@ services:
       --init-file /data/application/init.sql
       --binlog_expire_logs_seconds=604800
     ports:
-      - ${MYSQL_PORT}:3306
+      - ${EXPOSE_MYSQL_PORT}:3306
     volumes:
       - mysql_data:/var/lib/mysql
       - ./init.sql:/data/application/init.sql