QHeaderView is using QStyleOptionHeaderV2 which should later be used in
the subelements drawings. But since the subelement rect must be
adjusted, a copy is done - sadly only to QStyleOptionHeader so we're
loosing the V2 information.
Therefore explicitly check if it's a V2 and copy it over to the correct
structure.
Pick-to: 6.5 6.2
Fixes: QTBUG-97571
Change-Id: I1482f118e2114cd6ef21c2a800785bd9910c1c5b
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
7763b83c4c