Remove pointlessly setting the desktop widget as the job window

If there is no top-level widget (like is the case in  Plasma) this has no
effect other than breaking the Qt6 build.

See https://invent.kde.org/teams/frameworks-devs/kf6-workboard/-/issues/3#note_431586

applets/icon/iconapplet.cpp

@@ -8,7 +8,6 @@
 
 #include <QAction>
 #include <QApplication>
-#include <QDesktopWidget>
 #include <QDir>
 #include <QDropEvent>
 #include <QFileInfo>
@@ -468,7 +467,6 @@ void IconApplet::processDrop(QObject *dropEvent)
                       static_cast<Qt::KeyboardModifiers>(dropEvent->property("modifiers").toInt()));
 
         KIO::DropJob *dropJob = KIO::drop(&de, m_url);
-        KJobWidgets::setWindow(dropJob, QApplication::desktop());
         return;
     }
 }