[iOS] Implement Popup Blocker Action for Page Action Menu.

Implements "Always show" action for popup blocker feature rows. When
tapped, opens all blocked popups and sets content setting to ALLOW for
the site, matching the banner's behavior. Row disappears after action
is taken.

Adds GetBlockedPopups() method to BlockedPopupTabHelper to
enable opening the blocked popups.

Bug: 449996847
Change-Id: I5ffe6d95b73f25f9b135124bcc50d771506d3b5a
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/7023029
Reviewed-by: Sergio Collazos <sczs@chromium.org>
Commit-Queue: Sergio Collazos <sczs@chromium.org>
Reviewed-by: Adam Arcaro <adamta@google.com>
Auto-Submit: Ibrahim Kanouche <kanouche@google.com>
Cr-Commit-Position: refs/heads/main@{#1527189}