fix: restart apache2 after installing zabbix config (#9206)

Apache must restart to load zabbix-apache-conf. Without restart,
/zabbix endpoint returns 404 until manual intervention.

Author: AlphaLawless

install/zabbix-install.sh

@@ -108,7 +108,7 @@ else
   AGENT_SERVICE="zabbix-agent"
 fi
 
-systemctl restart zabbix-server
+systemctl restart zabbix-server apache2
 systemctl enable -q --now zabbix-server $AGENT_SERVICE apache2
 msg_ok "Started Services"