Upping this to P0 since string freeze is today.

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/98207b1741114f471968e110e4a5b26d044439bd

commit 98207b1741114f471968e110e4a5b26d044439bd
Author: Jordy Greenblatt <jordynass@chromium.org>
Date: Sat Sep 29 00:04:54 2018

[CrOS MultiDevice] Update notification/setup flow strings


Bug:  890425 
Change-Id: Id1150f263c6cd1fded5422b395ac94f0166687e2
Reviewed-on: https://chromium-review.googlesource.com/1252915
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Jordy Greenblatt <jordynass@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595261}
[modify] https://crrev.com/98207b1741114f471968e110e4a5b26d044439bd/ash/ash_strings.grd
[modify] https://crrev.com/98207b1741114f471968e110e4a5b26d044439bd/chrome/app/chromeos_strings.grdp

The following revision refers to this bug:
  https://chromium.googlesource.com/chromium/src.git/+/4d6abe74de73b4d004f03d43d9367048de2e8fae

commit 4d6abe74de73b4d004f03d43d9367048de2e8fae
Author: Jordy Greenblatt <jordynass@chromium.org>
Date: Sat Sep 29 01:31:35 2018

[CrOS MultiDevice] Update settings UI strings


Bug:  890425 
Change-Id: I8b8f3bc7751c94e01e44f781a732012f954fb7e2
Reviewed-on: https://chromium-review.googlesource.com/1252527
Reviewed-by: Demetrios Papadopoulos <dpapad@chromium.org>
Reviewed-by: Kyle Horimoto <khorimoto@chromium.org>
Commit-Queue: Jordy Greenblatt <jordynass@chromium.org>
Cr-Commit-Position: refs/heads/master@{#595284}
[modify] https://crrev.com/4d6abe74de73b4d004f03d43d9367048de2e8fae/chrome/app/settings_strings.grdp
[modify] https://crrev.com/4d6abe74de73b4d004f03d43d9367048de2e8fae/chrome/browser/resources/settings/multidevice_page/multidevice_subpage.html
[modify] https://crrev.com/4d6abe74de73b4d004f03d43d9367048de2e8fae/chrome/browser/ui/webui/settings/md_settings_localized_strings_provider.cc

The remainder of the string update is to fix the placeholder in the notification title for the 'Chromebook added' notification. In particular, it is not due by string freeze so this is no longer P0.

Because the remainder is covered by the P1 https://bugs.chromium.org/p/chromium/issues/detail?id=890521, I'm marking it a dupblicate and demoting it to a P1.