tst_QDateTimeEdit::editingRanged() remove setActiveWindow()

2f6fe3a268 has made calls to
QApplicationPrivate::setActiveWindow() redundant.

Remove redundant calls.

Task-number: QTBUG-121488
Change-Id: I812ca8a9615ffa0fae6228b0a09f4df6b1a91c09
Reviewed-by: Axel Spoerl <axel.spoerl@qt.io>

tests/auto/widgets/widgets/qdatetimeedit/tst_qdatetimeedit.cpp

@@ -1354,7 +1354,6 @@ void tst_QDateTimeEdit::editingRanged()
     });
 
     edit->show();
-    QApplicationPrivate::setActiveWindow(edit.get());
     if (!QTest::qWaitForWindowActive(edit.get()))
         QSKIP("Failed to make window active, aborting");
     edit->setFocus();