CDD: Update requirements for Android biometrics

Update biometric section to clarify security requirements and enforce
consistent biometric implementations. This ensures that biometric
solutions are correctly implemented and surfaced via the biometrics APIs,
and that their security is measured and tested appropriately.

Bug: 145928315
Test: make -j

Change-Id: I633980e0f8993eb5814451e57601c216e03adaa8
2 files changed