fix: standalone_mysql deploy template

[exuanbo]

Hi,

I'm not sure if this is the expected behavior, but on my machine

dnf/build/dnf_data/home/template/init/wait_for_mysql.sh

Line 12 in 4056efe

MYSQL_PASSWORD="${3:-${CUR_MAIN_DB_ROOT_PASSWORD:-$DNF_DB_ROOT_PASSWORD}}"

always have the default 88888888 value, so wait_for_mysql.sh hangs silently until it errors after the max retries.

CUR_MAIN_DB_ROOT_PASSWORD is set here

dnf/build/dnf_data/docker-entrypoint.sh

Lines 55 to 59 in 4056efe

	# 定义主数据库局部变量，优先使用MAIN_MYSQL_*，回退到MYSQL_*
	CUR_MAIN_DB_HOST=${MAIN_MYSQL_HOST:-$MYSQL_HOST}
	CUR_MAIN_DB_PORT=${MAIN_MYSQL_PORT:-$MYSQL_PORT}
	CUR_MAIN_DB_ROOT_PASSWORD=${MAIN_MYSQL_ROOT_PASSWORD:-$DNF_DB_ROOT_PASSWORD}
	CUR_MAIN_DB_GAME_ALLOW_IP=${MAIN_MYSQL_GAME_ALLOW_IP:-$MYSQL_GAME_ALLOW_IP}