Fix hang when utf line break is used
Break the loop: if adding an offset to the number of columns doesn't increase the line length, we break out of the loop to avoid an infinite loop on loading some files. Shift + Enter creates an utf break character which breaks the lenght calculation. Also added a reptition flag to avoid any other hang if there is a strange symbol. BUG:410402 ref:https://invent.kde.org/kde/krita/merge_requests/128