Revert "Clear UDFPS BiometricPrompt a11y messages after read by talkback"

This reverts commit d0ac6337.

Reason for revert: reverting to original accessibility state with announcements
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:928ef2944e153bd5a341a1001ed73c0f2a07665c)
Merged-In: I987eb33ca9192aff751510fc245bf6cb055b3428
Change-Id: I987eb33ca9192aff751510fc245bf6cb055b3428