distro-dependencies(fedora): Add python3-sphinxcontrib-qthelp

Fix

📦[florian@fedora-rawhide ~]$ cat /home/florian/kde/log/2024-06-18-03/extra-cmake-modules/build.log
# kde-builder running: 'ninja' '-j' '64'
# from directory:  /home/florian/kde/build/extra-cmake-modules
[1/2] sphinx-build html: see /home/florian/kde/build/extra-cmake-modules/docs/build-html.log
FAILED: docs/doc_format_html /home/florian/kde/build/extra-cmake-modules/docs/doc_format_html 
cd /home/florian/kde/build/extra-cmake-modules/docs && /usr/bin/sphinx-build -D man_make_section_directory=0 -c /home/florian/kde/build/extra-cmake-modules/docs -d /home/florian/kde/build/extra-cmake-modules/docs/doctrees -b html /home/florian/kde/src/extra-cmake-modules/docs /home/florian/kde/build/extra-cmake-modules/docs/html > build-html.log

Extension error:
Could not import extension ecm (exception: No module named 'sphinx.builders.qthelp')
ninja: build stopped: subcommand failed.