mark rainfallData.cpp as safety critical file

reasoning: we are reading a text file from disk without doing any sanity checks

Task-number: QTBUG-127255
Pick-to: 6.9 6.8
Change-Id: Ie911841541c7423b039a733091eaa65d21810b16
Reviewed-by: Tomi Korpipää <tomi.korpipaa@qt.io>

examples/graphs/3d/widgetgraphgallery/rainfalldata.cpp

@@ -1,5 +1,6 @@
 // Copyright (C) 2023 The Qt Company Ltd.
 // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
+// Qt-Security score:critical reason:data-parser
 
 #include "rainfalldata.h"
 #include <QtCore/qfile.h>