[Autofill] Apply deactivated style in the footer text of the popup

Impl: screen/9deDvjUcJdGh7kB

Follow-up CLs will apply deactivated style in the vector icons too.

Bug: 345709988
Change-Id: I1cf570074e8011c3e7ead3867bebab3c658701cb
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/5605735


Reviewed-by: Jan Keitel <jkeitel@google.com>
Commit-Queue: Adem Derinel <derinel@google.com>
Cr-Commit-Position: refs/heads/main@{#1312812}