Fix landscape layout of BiometricPrompt pattern screen

Test: Manual:
1. Enter "BiometricPrompt Demo" app.
2. Check "Allow device credential", uncheck "Require confirmation".
3. Check any Radio button. (e.g. Persist across configuration changes)
4. Rotate DUT to landscape mode.
5. Tap the "AUTHENTICATE" then deliberately unrecognized.
6. Tap "Use pattern" button.

Before: The pattern entry UI is clipped and the text is not visible.

After: The pattern entry UI fits on the screen and is interactable.

Fixes: 149545148
Change-Id: Iefc0a7ce60a8caeb537b46ec821df0ea4d80e843