Let biometric prompt button text wrap to new line

Fixes an issue where the buttons on the biometric prompt would fail to
wrap to a second line in order to accommodate long label text. This
caused the buttons to be truncated in some languages (e.g. Russian).

Test: On a Pixel 4 XL:
1. Ensure a lock pattern is set and Face Unlock is enabled
2. Set the system language to Russian (Russia)
3. Open wifi settings and select a saved network
4. Tap on the "Share" button for this network
5. Wait for Face Unlock to time out for the prompt
6. Rotate the device between portrait and landscape

Fixes: 158240727
Change-Id: I51da6b124ffcd867322ee699e3908847e1df7ecd