Fix snap package: printing and print-preview (backport !6947 to 1.4.x) (!6951) · Merge requests · Inkscape / inkscape · GitLab

Printing needs cups -> trigger host-side installation of the cups snap socket (or however it is called)
Print preview needs evince (which needs some further stuff) --> include it in the snap until a better solution is found

Fixes #1734 (closed) for 1.4.x