Core/Quests: Fix a CMSG injection abuse.

closes #15709

src/server/game/Handlers/QuestHandler.cpp

@@ -124,8 +124,7 @@ void WorldSession::HandleQuestgiverAcceptQuestOpcode(WorldPacket& recvData)
 
     if (Player* playerQuestObject = object->ToPlayer())
     {
-        if ((_player->GetDivider() && _player->GetDivider() != guid) ||
+        if ((_player->GetDivider() && _player->GetDivider() != guid) || !playerQuestObject->CanShareQuest(questId))
-           ((object != _player && !playerQuestObject->CanShareQuest(questId))))
         {
             CLOSE_GOSSIP_CLEAR_DIVIDER();
             return;