[WebsiteSettings] Adjust visual margins on permission bubble to match mocks.

R=markusheinz@chromium.org

Review URL: https://codereview.chromium.org/153973005

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@251246 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 251246