www/webkit2-gtk3: Update to 2.24.4

Changes: https://webkitgtk.org/2019/08/28/webkitgtk2.24.4-released.html
PR: 240196
Submitted by: tobik
Approved by: gnome (maintainer timeout, 2 weeks)
Security: e45c3669-caf2-11e9-851a-dcf3aaa3f3ff
MFH: 2019Q3