Chrome OS OOBE: Remove full-width CSS class

Remove the "full-width" CSS class from the code - it seems to have no
usage anymore.

Previously, this class was enabled during the SAML mode, however after
the SAML mode has been migrated to Gaia V2 API all CSS rules associated
with ".full-width" become overridden by other ones.

Bug: 470893
Test: manual - verify UI hasn't changed for OOBE/login/SAML interstitial pages
Change-Id: Id2dab371bc1d0da21501f1ce32ab07344e160480
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1617767
Reviewed-by: Alexander Alekseev <alemate@chromium.org>
Commit-Queue: Maksim Ivanov <emaxx@chromium.org>
Cr-Commit-Position: refs/heads/master@{#661179}
3 files changed