Fix#4201. Although that issue can be dealt with without any change to PhpSpreadsheet, it is pretty clear that `setLabelFont` has been accidentally omitted from Chart/Layout. Add it now. Xlsx Chart Writer is changed to use font name from labelFont if latin, eastAsian, or complexScript is uninitialized. Finally, chart label font size is multiplied by 100 in Xlsx Writer, as it is in Excel, but the corresponding division by 100 has been omitted from Xlsx Chart Reader - add that now.
oleibman