ImageMagick: update to 7.1.2.18 (include several security fixes)

[kaistian]

Over 55 CVEs is fixed ranging from score 4.0 to 8.6

Testing the changes

• I tested the changes in this PR: Briefly

Local build testing

• I built this PR locally for my native architecture, (x86-64-LIBC)

[ahesford]

Please don't submit updates you haven't tested.

[kaistian]

So how extensive should this test be?
I always check that the binary work, but wouldn't call that a very extensive test

magick --version
Version: ImageMagick 7.1.2-18 Q16-HDRI x86_64 4d7ebd363:20260322 https://imagemagick.org
Copyright: (C) 1999 ImageMagick Studio LLC
License: https://imagemagick.org/license/
Features: Cipher DPC HDRI Modules OpenCL OpenMP(4.5)
Delegates (built-in): bzlib cairo djvu fontconfig freetype gslib gvc heic jbig jng jp2 jpeg lcms lqr ltdl lzma openexr pangocairo png ps raqm rsvg tiff webp wmf x xml zlib zstd
Compiler: gcc (14.2)

[ahesford]

If you've at least run the products, I'd answer the testing question "briefly" rather than "no", but ideally you update packages that you actually use, and can at least confirm that your usual workflow doesn't break with the update.

[kaistian]

I use it, and only send PR on things installed on my computer, but did not have any images to convert at the moment.

Since it contains fix for several high scored CVEs it thought it would be better to get it in ASAP then wait to I have gotten around to convert some images.