[BUG] for mysql addon, syncer runs mysql with user 'postgres' and has a 'defunct' mysql child process

[nayutah]

Describe the bug

root 2158517 0.2 0.0 1238964 8960 ? Sl 06:52 0:05 /usr/bin/containerd-shim-runc-v2 -namespace k8s.io -id 872da11147f77566c938a958774972f8799d55dddfaff4316e0c41a9f613f6fd -address /run/containerd/containerd.sock
65535 2158538 0.0 0.0 1028 448 ? Ss 06:52 0:00 _ /pause
root 2159035 0.1 0.0 1279700 40768 ? Ssl 06:53 0:01 _ syncer --config-path /kubeblocks/config/components --port 3601 -- bash -c mv /var/lib/mysql/plugin/audit_log.so /usr/lib64/mysql/plugin/ rm -rf /var/lib/mysql/plugin chown -R mysql:root /var/lib/mysql skip_replica_start="OFF" if [ -f /var/lib/mysql/data/.restore_new_cluster ]; then skip_replica_start="ON" fi docker-entrypoint.sh mysqld --server-id $(( ${KB_POD_NAME##*-} + 1)) \ --plugin-load-add=rpl_semi_sync_source=semisync_source.so \ --plugin-load-add=rpl_semi_sync_replica=semisync_replica.so \ --plugin-load-add=audit_log=audit_log.so \ --log-bin=/var/lib/mysql/binlog/mysql-1x-mysql-0-bin \ --skip-replica-start=$skip_replica_start
postgres 2159094 131 13.9 29200548 18456448 ? Sl 06:53 40:37 | _ mysqld --server-id 1 --plugin-load-add=rpl_semi_sync_source=semisync_source.so --plugin-load-add=rpl_semi_sync_replica=semisync_replica.so --plugin-load-add=audit_log=audit_log.so --log-bin=/var/lib/mysql/binlog/mysql-1x-mysql-0-bin --skip-replica-start=OFF
postgres 2160463 0.4 0.0 0 0 ? Z 06:53 0:09 | _ [mysqld]
root 2159088 0.0 0.0 1604 896 ? Ss 06:53 0:00 _ /bin/sh /scripts/agamotto.sh
root 2159106 0.7 0.0 895592 107620 ? Sl 06:53 0:14 | _ /bin/agamotto --config=/opt/agamotto/agamotto-config.yaml
65532 2159210 0.2 0.0 1290724 48832 ? Ssl 06:53 0:04 _ lorry --port 3501 --grpcport 50001
65532 2159546 0.0 0.0 1277452 37184 ? Ssl 06:53 0:00 _ /bin/reloader --log-level info --operator-update-enable --tcp 9901 --config /opt/config-manager/config-manager.yaml

To Reproduce
Steps to reproduce the behavior:

1. create a mysql cluster
2. bench it
3. pstree the Pod containers

Expected behavior
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