When loading a user web map, the map extent should be updated to place that web map's content in view

[mikewilburn]

Low priority, but I noticed this while comparing the app the Nick's native iOS version. When he loads a user map, the map display is panned/zoomed to the web map's initial load extent.
In my opinion, this is slightly more intuitive behavior - it makes clear the web map is loaded. I don't think there is a need to ensure we preserve the active map extent on load as we're doing now.

[mikewilburn]

This has already been implemented for WPF for Mara's DevSummit demo.