Favicon urls should now be populated in database

[jasonrsadler]

Fixes brave/brave-browser#986.
Fixes brave-intl/bat-native-ledger#83

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).
• Verified that these changes build without errors on
  • Windows
  • macOS
  • Linux
• Verified that these changes pass automated tests (npm test brave_unit_tests && npm test brave_browser_tests) on
  • Windows
  • macOS
  • Linux
• Ran git rebase master (if needed).
• 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.
• Add appropriate QA labels (QA/Yes or QA/No) to include the closed issue in milestone

Test Plan:

1. Open Brave and enable rewards
2. Open youtube video on youtube website and view for required time
3. Verify the youtube publisher avatar url is added to the database

1. Open Brave and enable rewards
2. Open youtube video embedded on a website separate from youtube
3. Verify the youtube publisher avatar url is added to the database

Reviewer Checklist:

• New files have MPL-2.0 license header.
• Request a security/privacy review as needed.
• Adequate test coverage exists to prevent regressions
• Verify test plan is specified in PR before merging to source

[NejcZdovc]

master 1047e2c
0.56.x no change since #530 already updated hash
0.55.x no change since #530 already updated hash