sysutils/beats8: Update 8.19.13 => 8.19.15
Release Notes:
https://www.elastic.co/guide/en/beats/libbeat/current/release-notes-8.19.14.html
https://www.elastic.co/guide/en/beats/libbeat/current/release-notes-8.19.15.html
PR: 294181
Approved by: elastic (maintainer, timeout 3 weeks)
Sponsored by: UNIS Labs