qmapwidgethelper: move includes to the header

Add the following includes in the header -
<QVariant> and <QGeoCoordinate> otherwise the
mobile build fails.

It is unclear how the desktop build does not complain
about this.

Signed-off-by: Lubomir I. Ivanov <neolit123@gmail.com>

map-widget/qmlmapwidgethelper.cpp

@@ -1,7 +1,6 @@
 // SPDX-License-Identifier: GPL-2.0
 #include <QApplication>
 #include <QClipboard>
-#include <QGeoCoordinate>
 #include <QDebug>
 #include <QVector>
 

map-widget/qmlmapwidgethelper.h

@@ -3,8 +3,9 @@
 #define QMLMAPWIDGETHELPER_H
 
 #include <QObject>
+#include <QGeoCoordinate>
+#include <QVariant>
 
-class QGeoCoordinate;
 class MapLocationModel;
 class MapLocation;
 struct dive_site;