Maybe hide holding space welcome banner on directory change.

Previously we checked if we should show the holding space welcome banner
on directory change but we failed to hide it if it was already showing
but was no longer appropriate to be shown.

Bug: 1170506
Change-Id: I769c9181a6de9d7c6d3255374b37f8360f292b6b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2648435


Reviewed-by: Luciano Pacheco <lucmult@chromium.org>
Commit-Queue: David Black <dmblack@google.com>
Cr-Commit-Position: refs/heads/master@{#847407}