[ios] Only update the password managers of regular and otr Browsers

The inactive Browser never realize its active WebState, so it is
possible for the tab helpers to not exists. Additionally, the tab
are never presented directly, they first needs to be moved to the
regular Browser, so ignore the inactive Browser when updating the
password managers.

Bug: 432020830
Change-Id: I6d35f3e6a533f4af012b93e9ae61244b7127b7ea
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6849449
Reviewed-by: Vincent Boisselle <vincb@google.com>
Auto-Submit: Sylvain Defresne <sdefresne@chromium.org>
Commit-Queue: Sylvain Defresne <sdefresne@chromium.org>
Cr-Commit-Position: refs/heads/main@{#1505785}