Fixes type mismatch on 32-bit architectures.
/builddir/build/BUILD/kf6-kimageformats-6.13.0-build/kimageformats-6.13.0/src/imageformats/jxr.cpp: In member function ‘virtual bool JXRHandler::read(QImage*)’:
/builddir/build/BUILD/kf6-kimageformats-6.13.0-build/kimageformats-6.13.0/src/imageformats/jxr.cpp:994:88: error: no matching function for call to ‘min(qint64&, qsizetype)’
994 | std::memcpy(img.scanLine(y), ba.data() + convStrideSize * y, (std::min)(convStrideSize, img.bytesPerLine()));
| ~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~