Custom Vehicle Selector visual improvements

Custom vehicle selector now affected by theme change. Cosnistent with other actrive elements

custom-example/res/Custom/Widgets/CustomVehicleButton.qml

@@ -47,7 +47,7 @@ Button {
 
     background: Rectangle {
         anchors.fill:               parent
-        color:                      button.checked ? qgcPal.window : qgcPal.button
+        color:                      button.checked ? qgcPal.buttonHighlight : qgcPal.button
         radius:                     ScreenTools.defaultFontPixelWidth * 0.5
     }