This patch makes a few changes to bring the protections panel closer in line
with the Proton spec:
1) Add a few pixels of width to the tracking protection toggle switch.
2) Add underlining to the "site not working" link.
3) Replace the borders between sections of the panel with toolbarseparator
elements, so that they become narrower than the panel width (and also
match the panel header's separator).
Differential Revision: https://phabricator.services.mozilla.com/D111717
c69fee2a81