net-mgmt/zabbix52: Update to 5.2.7

Changelog: https://www.zabbix.com/rn/rn5.2.7
Differential Revision: https://reviews.freebsd.org/D30966

Approved by: pg@pakhom.spb.ru (maintainer)

(cherry picked from commit db1f820bf89b1e72a3d24fc159c15401c3fba716)