81b37a519c
Using autofocus="true" or programmatically calling .focus() when there is no pre-existing focused
element causes the :focus-visible to match.
This patch avoids using autofocus="true" on some of our about: pages, and uses
Element.focus({ preventFocusRing: true }) to avoid that when these pages and dialog
first load. Note that this doesn't prevent the focus ring from _ever_ appear, it just
stops it from appearing on first load.
Differential Revision: https://phabricator.services.mozilla.com/D115062