Imagick is a PHP module that handles images, compression, image conversion and cropping, so your site can deliver images without scaling issues.
Sadly, WordPress doesn’t provide a method for hiding recommendations and notifications in Site Health. Your best bet is to reach out to your web hosting support team and ask them to upgrade the version of PHP that powers your web server, so the Imagick error will be resolved. Chances are, it’s likely an issue for every other site that is hosted on the same server.
Hope this helps!