Removes empty elements on CoinMarketCap

[jonathansampson]

Fixes #12755

Submitter Checklist:

• Submitted a ticket for my issue if one did not already exist.
• Used Github auto-closing keywords in the commit message.
• Added/updated tests for this change (for new code or code which already has tests).
• Ran git rebase -i to squash commits (if needed).
• Tagged reviewers and labelled the pull request as needed.
• Request a security/privacy review as needed. (Ask a Brave employee to help if you cannot access this document.)

Test Plan:

1. Navigate to CoinMarketCap
2. Confirm that empty elements in header and footer are collapsed/removed

Reviewer Checklist:

• Request a security/privacy review as needed if one was not already requested.

[bbondy]

@bsclifton would you be able to land this with 0.20.x?

[bsclifton]

@bbondy sure thing 😄 👍

[bsclifton]

master a3b96a2
0.21.x c68b3e7
0.20.x cc73feb