[UB] Fix UB visibility bugs

Two changes that should address these bugs:
1) Always update the visibility of the icon in StatusChanged, even if
`icon_visible_` is the same. This is because visibility is not just a
product of `icon_visible_`, so it's possible a separate change in the UI
(e.g. omnibox focus) has triggered this call and we need to update

2) Keep track of whether or not we should be showing the UB icon on the
current site as a confirmation of the user changing their protection
state. This avoids the logic from 1) suddenly causing the UB icon to
disappear after animating (e.g. if the site has not taken any action
that we would typically show UB for). Note that leaving the site and
then going back may not cause the icon to show for these cases, which
is WAI as we only want to show UB on the site **directly after** a
protection state change / reload

Bug: b:432231780, b:432365741, b:432382207
Change-Id: I9a39c9fa5a3fbe7cff5a4d3345943ed76b3539fe
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/6777768
Auto-Submit: Fiona Macintosh <fmacintosh@google.com>
Reviewed-by: Michelle Abreo <michelleabreo@google.com>
Commit-Queue: Michelle Abreo <michelleabreo@google.com>
Cr-Commit-Position: refs/heads/main@{#1490844}