hplip: patch imageProcessor segfault in `hpcups` (#58949)

Beginning with version 3.18.7, `hpcups` fails with
> DEBUG: imageProcessorStartPage failed
and segfaults (tested with HP LaserJet 1000 printer).

Upstream bug reports:
* https://bugs.launchpad.net/hplip/+bug/1788706
* https://bugs.launchpad.net/hplip/+bug/1787289

There is a patch available in one of the reports:
https://bugs.launchpad.net/hplip/+bug/1787289/+attachment/5176026/+files/hplip.patch
It applies to 3.18.7, but not to later versions.

This commit adds a slight adaption of
the patch that applies to versions 3.18.9 -- 3.19.6.
The patch fixes https://github.com/NixOS/nixpkgs/issues/58949 .

Note that the patch is merely a workaround:
It simply removes all calls into the
ImageProcessor library from `HPCupsFilter.cpp`.