[Client] Guard dragged card ghost from painting or dropping deleted cards (#7688)

* [Client] Guard dragged card ghost from painting or dropping deleted cards

* [Game] Revert handling for cards destroyed mid-drag

Co-authored-by: sentry[bot] <39604003+sentry[bot]@users.noreply.github.com>

* [DeckView] Access pointer through QPointer in DeckViewCardDragItem

---------

Co-authored-by: sentry[bot] <39604003+sentry[bot]@users.noreply.github.com>
Co-authored-by: zeldazach <7460172+zeldazach@users.noreply.github.com>

cockatrice/src/game_graphics/deckview/deck_view.cpp

@@ -77,7 +77,7 @@ void DeckViewCardDragItem::updatePosition(const QPointF &cursorScenePos)
 
 void DeckViewCardDragItem::handleDrop(DeckViewCardContainer *target)
 {
-    auto *card = static_cast<DeckViewCard *>(item);
+    auto *card = static_cast<DeckViewCard *>(item.data());
     auto *start = static_cast<DeckViewCardContainer *>(item->parentItem());
     start->removeCard(card);
     target->addCard(card);