Do not check isOobeUi() when demo mode accelerator is triggered.

Showing demo mode setup UI is already guarded by the appropriate
screen group check. This check is sufficient.

Change-Id: I61478bb0e0a4933a2f6869781b7a9b115d926f08
Reviewed-on: https://chromium-review.googlesource.com/1104974


Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Aga Wronska <agawronska@chromium.org>
Cr-Commit-Position: refs/heads/master@{#568125}