GitLab

This CL removes NOTIFICATION_KIOSK_ENABLED and
NOTIFICATION_KIOSK_APPS_LOADED notifications.
These were used for the tests. Replaced with
ash::LoginScreenTestApi::WaitForUiUpdate

I'm gonna fix KioskErrorScreenTest.OpenCertificateConfig in a separate
CL

Bug: none
Change-Id: I61a19f708683c16d7a2ec764a29a978c023893e8
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2544523Reviewed-by: Marc Treib <treib@chromium.org>
Reviewed-by: Anatoliy Potapchuk <apotapchuk@chromium.org>
Commit-Queue: Roman Sorokin [CET] <rsorokin@chromium.org>
Cr-Commit-Position: refs/heads/master@{#828806}