Minor adjustments to chrome://safe-browsing

This change fixes the issue with auto-scrolling when you select the
database manager tab, and also adds a border around password protection
pings so you can tell one ping from the other a bit more easily.

Render of two pings: https://screenshot.googleplex.com/4HprtXGmXpg.png

Bug: 984519
Change-Id: Id2fad0cb23c0c142c85a77c2a56e88fda9e7cd68
Reviewed-on: https://chromium-review.googlesource.com/c/chromium/src/+/1790328
Auto-Submit: Daniel Rubery <drubery@chromium.org>
Reviewed-by: Varun Khaneja <vakh@chromium.org>
Commit-Queue: Varun Khaneja <vakh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#694382}