CVE-2026-14544: complete the incomplete CVE-2026-8631 integer overflow fix
in the hpcups processing path (PCLmGenerator::Encapsulate), so the full
whiteStripLen * srcNumComponents product is overflow-checked (backport of
RHEL/AlmaLinux hplip-3.21.2-6.el9_8.5, RHSA-2026:40831)