For a11y, assertively announce primary biometric messages

Fixes: 322889148
Flag: ACONFIG com.android.systemui.device_entry_udfps_refactor NEXTFOOD
Test: atest KeyguardIndicationControlerTest
Test: manually enable talkback, enroll fingerprint,
then intentionally fail fingerprint on the lockscreen (with
other rotating messages). Observe that talk back announces
the fingerprint failures and erorrs.

Change-Id: I227901b87cc91d5be5414f87fd97e744fe67329b