ImageMagick: Heap buffer overflow when encoding JXL image with a 16-bit float

ImageMagick is free and open-source software used for editing and manipulating digital images. In versions below 7.1.2-19, the JXL encoder has an heap write overflow when a user specifies that the image should be encoded as 16 bit floats. This issue has been fixed in version 7.1.2-19.