The height of the items of the generic wxListCtrl remained too small if an
image of a greater than standard size was used.
Fix this by forcing the line height recalculation when adding an item using an
image higher than the current line height.
Closes#12806.
git-svn-id: https://svn.wxwidgets.org/svn/wx/wxWidgets/trunk@67615 c3d73ce0-8a6f-49c7-b76d-6d57e0e08775