[PATCH] QSortFilterProxyModel: don't call index(row, 0) if there are no columns

This is invalid, e.g. it asserts in
QConcatenateTablesProxyModel::index()

Fixes: QTBUG-134210
Change-Id: I21acad9497d423b0366991296e8dd498d51395ea
Reviewed-by: Volker Hilsheimer <volker.hilsheimer@qt.io>
(cherry picked from commit 93694e99c214a5166fc842f92659e42260230dce)
Reviewed-by: Qt Cherry-pick Bot <cherrypick_bot@qt-project.org>
Gbp-Pq: Name upstream_prevent_recursion_in_qsortfilterproxymodel.diff

qt6-base (6.8.2+dfsg-6) unstable; urgency=medium

  [ Patrick Franz ]
  * Backport patch to fix issue when configuring Plasma to have multiple
    Notification widgets, fixes QTBUG-134210.
  * Backport patch to fix CVE-2025-3512 (Closes: #1103022).
  * Let qt6-gtk-platformtheme depend on gnome-themes-extra-data to fix
    issue with dark themes (Closes: #1095836).

  [ Pino Toscano ]
  * Bump Standards-Version to 4.7.2, no changes required.

[dgit import unpatched qt6-base 6.8.2+dfsg-6]

Import qt6-base_6.8.2+dfsg-6.debian.tar.xz

[dgit import tarball qt6-base 6.8.2+dfsg-6 qt6-base_6.8.2+dfsg-6.debian.tar.xz]

Import qt6-base_6.8.2+dfsg.orig.tar.xz

[dgit import orig qt6-base_6.8.2+dfsg.orig.tar.xz]