sysutils/beats8: Fix panic, SIGSEGV in elastic-agent-libs/monitoring

Upstream:
https://github.com/elastic/elastic-agent-libs/issues/392
https://github.com/elastic/elastic-agent-libs/pull/402

PR: 294181
Approved by: girgen (elastic)
Sponsored by: UNIS Labs
MFH: 2026Q2

(cherry picked from commit 7dc442bb668b58fcf34b7c8e423b4ffd3c9844dc)