Preview of Document scanner is on some devices in landscape and result in poor quality

**Describe the bug**
On some devices the preview is in landscape (eg. Samsung Active Tab 3). So most of the sensor area is cropped and result in poor quality.

**To Reproduce**
Use a Samsung Galaxy Active Tab 2 or 3. Maybe with many other devices possible?


**Expected behavior**
Force a portrait preview and use the whole sensor area of the camera.
Provide an option to use a specific preview size, so we can find the best preview size for specific devices.

**SDK Info:**
play-services-mlkit-document-scanner = { module = "com.google.android.gms:play-services-mlkit-document-scanner", version.ref = "16.0.0-beta1"}

**Smartphone:**
Samsung Galaxy Tab Active 3 (SM-T575) - Android 11
Samsung Galaxy Tab Active 2 (SM-T395) - Android 9