When the view was already sorted by the column and order given to
sortByColumn(), a resort was not triggered which is a regression since
d0f909f8db.
Therefore don't rely on sortIndicatorChanged() in this case and trigger
an explicit sort as it's done when no user-triggered sorting is enabled
Fixes: QTBUG-86268
Change-Id: I3ec30ab81f304d5a19cef6d67b8a81c21b4a112d
Pick-to: 5.15
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>
3ddffd2d8b