graphics/ImageMagick6: update to 6.9.13-50

Changes: https://github.com/ImageMagick/ImageMagick6/compare/6.9.13-36...6.9.13-50
Security: CVE-2026-24481
Security: CVE-2026-24484
Security: CVE-2026-24485
Security: CVE-2026-25576
Security: CVE-2026-25638
Security: CVE-2026-25795
Security: CVE-2026-25796
Security: CVE-2026-25797
Security: CVE-2026-25798
Security: CVE-2026-25799
Security: CVE-2026-25897
Security: CVE-2026-25898
Security: CVE-2026-25965
Security: CVE-2026-25966
Security: CVE-2026-25968
Security: CVE-2026-25970
Security: CVE-2026-25971
Security: CVE-2026-25982
Security: CVE-2026-25983
Security: CVE-2026-25985
Security: CVE-2026-25986
Security: CVE-2026-25987
Security: CVE-2026-25988
Security: CVE-2026-25989
Security: CVE-2026-26066
Security: CVE-2026-26283
Security: CVE-2026-26284
Security: CVE-2026-26983
Security: CVE-2026-27798
Security: CVE-2026-27799
Security: CVE-2026-28494
Security: CVE-2026-28686
Security: CVE-2026-28687
Security: CVE-2026-28688
Security: CVE-2026-28689
Security: CVE-2026-28690
Security: CVE-2026-28691
Security: CVE-2026-28692
Security: CVE-2026-28693
Security: CVE-2026-30883
Security: CVE-2026-30929
Security: CVE-2026-30936
Security: CVE-2026-30937
Security: CVE-2026-31853
Security: CVE-2026-32259
Security: CVE-2026-32636
Security: CVE-2026-33535
Security: CVE-2026-33536
Security: CVE-2026-33899
Security: CVE-2026-33900
Security: CVE-2026-33901
Security: CVE-2026-33902
Security: CVE-2026-33905
Security: CVE-2026-33908
Security: CVE-2026-34238
Security: CVE-2026-40310
Security: CVE-2026-40311
Security: CVE-2026-42050
Security: CVE-2026-42326
Security: CVE-2026-45031
Security: CVE-2026-45358
Security: CVE-2026-45359
Security: CVE-2026-45624
Security: CVE-2026-45664
Security: CVE-2026-46520
Security: CVE-2026-46521
Security: CVE-2026-46522
Security: CVE-2026-46523
Security: CVE-2026-46559
Security: CVE-2026-46692
Security: CVE-2026-46693
Security: CVE-2026-47165
Security: CVE-2026-47166
Security: CVE-2026-48733
Security: CVE-2026-48734
Security: CVE-2026-48994
Security: CVE-2026-49218
Security: CVE-2026-49219
Security: CVE-2026-53460
Security: CVE-2026-53461
Security: CVE-2026-53462
Security: CVE-2026-53463
Security: CVE-2026-56367
Security: CVE-2026-56378
PR: 296189

(cherry picked from commit 338d53d7cde6e748f0b1635e0ac57d4d17f886ae)