Add safe area to static barcode scanner screen on iOS

[pchasco]

When using the default scanner screen on iOS devices without a physical home button, the buttons at the bottom of the page are overlapped by the system UI, and are generally just too close to the screen bottom edge and corners.

It would be ideal if some padding could be added to the bottom of the screen to inset the controls. Keep in mind that the iPhone corners are rounded, so the Cancel and rotate buttons are clipped by the physical device's corners, which you cannot see in the screenshot.