site-specific Bravery settings headers should disappear when the list is empty

[srirambv]

Did you search for similar issues before submitting this one?

Describe the issue you encountered:
HTTPSE is not shown under site-specific Bravery settings. Only comes up when HTTPSE is disabled on a site and when the site specific setting is deleted, HTTPSE doesn't show under the site specific settings

Expected behavior:
Should always shows the label under Bravery settings similar to the other ones

• Platform (Win7, 8, 10? macOS? Linux distro?):
  Windows 10 x64
• Brave Version:
  0.12.2 RC4
• Steps to reproduce:
  1. Open preferences page about:preferences#shields
  2. HTTPSE not listed under Saved Site Exceptions
  3. Visit http://travelchannel.com/video, disable HTTPSE for the site
  4. HTTPSE is now listed under saved site exceptions
  5. Delete the new exception listed under HTTPSE, HTTPSE disappears from the list
• Screenshot if needed:
  
• Any related issues:
  Add option to clear site-specific Bravery settings #2545 add right-click to delete ledger entry, add Bravery site settings page #4118

[diracdeltas]

They should actually all disappear from the list when empty

[bbondy]

Included in 0.12.3RC3