Revert "Clear UDFPS lockscreen and alternate bouncer a11y messages after read by talkback"

This reverts commit cf9a0559.

Reason for revert: reverting to original accessibility state
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:f7170344e26c09afa2684d7c123ab750fca702c1)
Merged-In: I02980a86a2d7d7bd79f2c22e97366ffcbcea6ba6
Change-Id: I02980a86a2d7d7bd79f2c22e97366ffcbcea6ba6