Fixed large translucent element which obscures Washington Post content

[jonathansampson]

Test plan

1. Navigate to any article on washingtonpost.com
2. Scroll down to read the article
3. After scrolling down, there should NOT be a full-width bar across the top of the content (see screenshot below)

Original issue description

• Did you search for similar issues before submitting this one?
  Yes

• Describe the issue you encountered:
  Brave removes ads from Washington Post, but leaves a large and unsightly element behind. This element obscures the central material on the page.

• Platform (Win7, 8, 10? macOS? Linux distro?):
  Desktop

• Brave Version (revision SHA):
  0.13.5

• Steps to reproduce:

  1. Navigate to any article on washingtonpost.com
  2. Scroll down to read the article
  3. Note the full-width bar across the top of the content

• Actual result:
  Brave successfully removes ads/trackers, but leaves the site somewhat marred.

• Expected result:
  The aesthetics of Washington Post should not be hurt by Brave's ad/tracker protection.

• Will the steps above reproduce in a fresh profile? If not what other info can be added?
  Yes

• Is this an issue in the currently released version?
  Yes

• Can this issue be consistently reproduced?
  Yes

• Screenshot if needed: