add image for non-existent domain error page

refs: CNVS-10531

Adds an image used in the changes for g/30445.

Change-Id: If5c76a09839fb9e2c0dffc0d5f5f1ef403495e04
Reviewed-on: https://gerrit.instructure.com/30443
Tested-by: Jenkins <jenkins@instructure.com>
Reviewed-by: Anthus Williams <awilliams@instructure.com>
Reviewed-by: Jacob Fugal <jacob@instructure.com>
QA-Review: August Thornton <august@instructure.com>
Product-Review: Nick Cloward <ncloward@instructure.com>