`KIO::iconNameForUrl()` was doing a lot of redundant work on file items that `KFileItem::iconName()`
already does for us. Thispatch moves most of that logic into `KFileItem::iconName()` when operating
on local files (not for remote files, which may be slower, and for which we don't want to stat).
BUG: 356045
FIXED-IN: 5.60