[Passwords] Recheck edited passwords for weakness

This change implements checking a password for weakness after it has
been modified in the Desktop Password Check UI. In case the new password
is / remains weak, and will be added / kept in the section of weak
passwords.

Fixed: 1142377
Change-Id: I03ffc9c087059926fe3f12a50594317235f5383b
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/2514379
Commit-Queue: Jan Wilken Dörrie <jdoerrie@chromium.org>
Reviewed-by: Friedrich [CET] <fhorschig@chromium.org>
Cr-Commit-Position: refs/heads/master@{#823560}