When pressing an index in order to start a flick gesture, QAIV sets
the current index. When QScroller changes state to Dragging, then
QAIV restores the current index to what it was before the press, as
the user is clearly scrolling the view. With autoScroll enabled, this
will produce an ugly jump if the old current index is no longer in
the viewport.
To prevent this, disable autoScroll before restoring the currentIndex.
Fixes: QTBUG-64543
Pick-to: 6.2 6.1 5.15
Change-Id: I3e0a18a6a179d80b9d810fce5aa658f0cfff9a29
Reviewed-by: Richard Moe Gustavsen <richard.gustavsen@qt.io>