QGCButton.qml: hover disabled on mobile:

For some reason in mobile the button would keep as hovered
even if it is not pressed, so it was weird. This way it
makes more sense for mobile, the UI is consistent with
what is happening

src/QmlControls/QGCButton.qml

@@ -7,7 +7,7 @@ import QGroundControl.ScreenTools 1.0
 
 Button {
     id:             control
-    hoverEnabled:   true
+    hoverEnabled:   !ScreenTools.isMobile
     topPadding:     _verticalPadding
     bottomPadding:  _verticalPadding
     leftPadding:    _horizontalPadding