textproc/libxml2: Update to 2.14.4

Fixes multiple CVEs:
CVE-2025-32415
CVE-2025-32414
CVE-2025-27113
CVE-2025-24928
CVE-2024-56171

Changelog: https://gitlab.gnome.org/GNOME/libxml2/-/releases/v2.14.4

Backport upstream commits:
19de8b47b1fe4b87b06bc6b89f5ee9697870a0ad
5700d989cc18889e1601c651ad69a41af8b32073
d3e33dc214276498e73b61188be02b2863c9670a
cf52139b4170be13b51b62da11c208dc66e6eff0
356542324fa439de544b5e419b91ae68d42c306c

References:
https://gitlab.gnome.org/GNOME/libxml2/-/commit/19de8b47b1fe4b87b06bc6b89f5ee9697870a0ad
https://gitlab.gnome.org/GNOME/libxml2/-/commit/5700d989cc18889e1601c651ad69a41af8b32073
https://gitlab.gnome.org/GNOME/libxml2/-/commit/d3e33dc214276498e73b61188be02b2863c9670a
https://gitlab.gnome.org/GNOME/libxml2/-/commit/cf52139b4170be13b51b62da11c208dc66e6eff0
https://gitlab.gnome.org/GNOME/libxml2/-/commit/356542324fa439de544b5e419b91ae68d42c306c

PR: 279705, 287391
Approved by: ports-sec (tz) via PR 287391
Exp-runs by: antoine (previous iterations)