graphics/diff-pdf: Update to 0.4.1

Changelog (https://github.com/vslavik/diff-pdf/releases):

• Added new useful options: --skip-identical only outputs pages with actual differences --channel-tolerance makes it easy to ignore tiny differences --mark-differences adds visual markers to the margin to highlight where small changes are
• Fixes some bugs

PR: 245133
Submitted by: Zsolt Udvari <uzsolt@uzsolt.hu> (maintainer)