ivi-shell: remove ivi_layout_get_screen_from_id API

The controller plugins does not use ivi screens for IVI layout APIs.
They use weston outputs directly. Therefore, this API is unnecessary.

Signed-off-by: Emre Ucan <eucan@de.adit-jv.com>
Reviewed-by: Pekka Paalanen <pekka.paalanen@collabora.co.uk>
Acked-by: Wataru Natsume <wnatsume@jp.adit-jv.com>