Accept QContextMenuEvent in ContextMenu

In case QQuickDeliveryAgentPrivate::deliverContextMenuEvent() doesn't
choose the correct target the first time, we need to let it propagate,
as with all other input events. But it should stop when it's actually
handled.

Pick-to: 6.9
Change-Id: I086f87a90c596d93688033f1ae63f258f508d36e
Reviewed-by: Jan Arve Sæther <jan-arve.saether@qt.io>

src/quicktemplates/qquickcontextmenu.cpp

@@ -108,6 +108,7 @@ bool QQuickContextMenu::eventFilter(QObject *object, QEvent *event)
         const QPoint posRelativeToParent(attacheeItem->mapFromScene(contextMenuEvent->pos()).toPoint());
         qCDebug(lcContextMenu) << this << "is showing menu instance" << menu << "at" << posRelativeToParent;
         menu->popup(posRelativeToParent);
+        event->accept();
         return true;
     }
     default: