Use QListIterator in qt6

src/importmailpluginmanager.cpp

@@ -38,7 +38,11 @@ ImportMailPluginManager *ImportMailPluginManager::self()
 bool ImportMailPluginManager::initializePluginList()
 {
     const QVector<KPluginMetaData> plugins = KPluginMetaData::findPlugins(QStringLiteral("importwizard"));
+#if QT_VERSION < QT_VERSION_CHECK(6, 0, 0)
     QVectorIterator<KPluginMetaData> i(plugins);
+#else
+    QListIterator<KPluginMetaData> i(plugins);
+#endif
     i.toBack();
     while (i.hasPrevious()) {
         ImportMailPluginManagerInfo info;