Fix NTLM domain parsing with Qt6
KNTLM::getAuth relies on isNull/isEmpty to distinguish the twp cases here, and with Qt5 this happened to work. With Qt6 QString::section returns a null string for an empty section though.
KNTLM::getAuth relies on isNull/isEmpty to distinguish the twp cases here, and with Qt5 this happened to work. With Qt6 QString::section returns a null string for an empty section though.