graphics/leptonica: Update to 1.82.0

If graphics/tesseract is installed and then graphics/opencv is to be
installed, OpenCV uses TesseractConfig.cmake to check for the presence
of Leptonica and wants to use FindLeptonica.cmake for that. Therefore
the new version adds a file cmake/FindLeptonica.cmake.

After switching from autotools to cmake, the libraries are named as
libleptonica.so instead of liblept.so. Upstream it is not yet decided
which naming will be used in the future [1]. As a workaround, the port
links the new naming to the previous one, since several dependent ports
still use the old names of the libraries.

[1] https://github.com/DanBloomberg/leptonica/issues/253

Changelog: https://github.com/DanBloomberg/leptonica/compare/1.76.0...1.82.0

PR: 260079

Co-authored-by: Daniel Engberg <diizzy@FreeBSD.org>