CrOS - Fix login screen pin pad issue

Fix an issue on the login screen that caused the pin pad
on the login/lock screen to vanish when hiding the virtual
keyboard that is used in tablet mode.

Fixed: 1129183
Change-Id: I2facd941f0201c0c7d5924528f352a07f3638305
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2437377Reviewed-by: Roman Sorokin [CET] <rsorokin@chromium.org>
Commit-Queue: Renato Silva <rrsilva@google.com>
Cr-Commit-Position: refs/heads/master@{#811776}

ash/login/ui/lock_contents_view.cc

@@ -1467,7 +1467,7 @@ void LockContentsView::OnKeyboardVisibilityChanged(bool is_visible) {
     return;
 
   keyboard_shown_ = is_visible;
-  LayoutAuth(CurrentBigUserView(), nullptr /*opt_to_hide*/, false /*animate*/);
+  LayoutAuth(CurrentBigUserView(), nullptr /*opt_to_hide*/, true /*animate*/);
 }
 
 void LockContentsView::SuspendImminent(