[TIMOB-27997] iOS: Ti.Blob images from device (via Ti.UI.View#toImage()) would report dimensions in points, not pixels

On Android, if we generate a Ti/Blob image from calling Ti.UI.View#toImage(), it reports width/height/size properly. On iOS, it will report width and height in points, not pixels. size is therefore also incorrect. Say we have a 10px x 10px view rendered to image on a 3x scale device. The blob will report width of 3, height of 3 and size of 9. The device will report density factor of 3. So naively multiple by that still gives us wrong values (of 9, 9, 81 respectively instead of 10, 10, 100). UIImage holds a scale value for cases like this and we should multiply width/height by that on iOS to get true pixel values. (Doing so in this case we actually do end up with 10, 10, 100 because presumably the image scale is recorded as something like 3.3333?)