Rebase to upstream 6.9.13.50, matching EPEL 8 ImageMagick-6.9.13.50-1.el8
Drop the TuxCare CVE patches whose fixes are included in the upstream
6.9.13.50 release
Keep the MSL empty-image crash fix (partial backport of upstream
fde1f305, not present in the legacy 6.x line)
CVE-2026-45664: free the chunk buffer on the MNG LOOP/ENDL op-cap abort
path (upstream dd198f960, not yet included in 6.9.13.50) to prevent a
heap memory leak when the loop-operation limit is hit