A bug was observed on Safari where the visibility policy switcher
popover was shrinking beyond the width of the policy switcher, hiding
a portion of the switcher component.
This was due to the presence of the `width: min-content` on the
popover for supporting dynamic popover menu sizing based on the content
of the menu items, in tandem with some issue in Safari since it worked
fine on other browsers.
This commit adds the `.popover-menu-label` class to the visibility
policy switcher's label to enforce `max-content` width on the label
element, which in turn fixes the popover shrinking issue on Safari.
As part of the popover menu redesign, this updates the topic visibility
popover to use the new "popover-menu" popover theme and improves
accessibility by using appropriate ARIA attributes.
This also moves the `:focus-visible` CSS rule to apply to any tab
picker in a popover, removing the need to explicitly add it to each
tab picker.
Fixes part of #28699.
Sayam Samal
Sayam Samal
Prakhar Pratyush
Aman Agrawal