Android: app freeze + fix

[softlion]

Please replace this incorrect code which triggers app freeze when real async image sources are used (like SvgImageSource from https://github.com/softlion/XamSvg-Samples).

Replace in https://github.com/NAXAM/mapbox-xamarin-forms/blob/master/Naxam.Mapbox.Platform.Droid/Extensions/ImageSourceExtensions.cs

            return handler?
                .LoadImageAsync(source, context).Result;

With this correct code:

            return handler?
                .LoadImageAsync(source, context).GetAwaiter().GetResult();

Or better: make this method async.