Only announce for accessibility if accessibility is enabled

Otherwise SystemUI will crash. Also, do not recycle events for now due to
b/134608331. Otherwise SystemUI will crash as well.

Fixes: 134603979
Bug: 134608331

Test: Do not enable talkback, successful auth does not crash now
Test: Enable talkback, successful auth also works
Change-Id: I5779a1a79a6504520d592e688ff9a48b6ea277d3