Fix pin error scenario for talkback.

There were a couple of issues with the accessibility of the wrong pin
scenario.

1. the user activity signal from the password view is trying to set the
   error message to an empty string. Move setting the error message to
   after resetting the password view.
2. No text is set yet while we are animating the view and this prevents
   the text from being announced. I remedied this by relying on a
   textwatcher to keep track of the textview.
3. The password view is constantly being selected, which shouldn't
   really be the case. This is because we set the input to be disabled
   as we check the password and re-enable it. While in this process, we
   requestfocus if focus is not on the password view.
4. For some reason we set the textview to "wrong pin" and then
   immediately an empty string. There is a 250ms delay to make the
   accessibility announcement. After 250ms, we want to ensure that the
   text is still displayed in the textview.

Consequently, once a wrong pin in inputted, the only talkback text is now
"Wrong Pin"

Fixes: 281635711
Fixes: 281787557
Test: wrong pin scenario in bouncer.
Test: password, simpin, and sim puk views.
Change-Id: I018e067e0a3b17fbd7921f40924ced401707297c