There is zabbix_server (Zabbix) 4.4.4 and Grafana v6.5.3
A template with problems from Zabbix is configured, it is possible to confirm problems, but is it possible to close them from the interface of Grafana itself?
I assume that you are using the Zabbix Grafana Plugin from Alexander Zobnin.
Regarding your request: It's not possible right now, but there's a feature request about it.