Material Showcase: Camera view of barcode scanner not fullscreen

I have been tinkering with the details of the barcode scanner sample in the material showcase app. On my Sony XPERIA XZ2 running Android 10, the camera view is not fullscreen though. There is a black bar at the bottom of the screen. I have taken a screenshot where I made this more obvious by removing the scrim and changing the background color of the activity to white.

I am new to Android and Kotlin and have so far been unable fully understand CameraSourcePreview code. Where do I need to make adjustments in order to change this behavior?