Restore usage of setProperty on Map.fitViewportToGeoShape

setProperty was initially introduced with
2867f1ef

 to animate center and zoom
level, if an animation was present, but then removed.
This change restores it.

Change-Id: Id1f6da820b6cccb62b18eeb78d7dba21ebc073bc
Reviewed-by: Alex Blasche <alexander.blasche@qt.io>