Clear "Wrong pattern" prompt automatically.

When the user enters a wrong pattern/pin/password, a "Wrong
pattern/pin/password" text shows up on ConfirmLockPattern or
ConfirmLockPassword screen. In ConfirmLockPassword, it disappears
automatically after 3 seconds, whereas it doesn't in ConfirmLockPattern.

In this change, we make the prompt in ConfirmLockPattern disappear
automatically as well.

Bug: 64781905
Test: manual
Test: make RunSettingsRoboTests
Change-Id: I53a25576413671ced4197064d51fbcc397733265