[ChangeLog][QtGui][QDesktopServices] URL handlers that have been passed
to setUrlHandler() must now be removed by calling unsetUrlHandler()
before they are destroyed. Relying on the handler's destructor to
implicitly unset it is now deprecated, because it may already be in use
by concurrent openUrl() calls. Support for implicit unsetting will be
removed in 6.6 and, until then, a qWarning() is raised if it is
exercised.
Fixes: QTBUG-100775
Fixes: QTBUG-100779
Pick-to: 6.3 6.2 5.15
Change-Id: I0c4f91b78f847b135fdeb38766babc892bdc1379
Reviewed-by: Qt CI Bot <qt_ci_bot@qt-project.org>
Reviewed-by: Sona Kurazyan <sona.kurazyan@qt.io>
37a25fce94