Make a static size for a favicon at about:newtab. Fixes #11132

[MargarytaChepiga]

Issue #11132
Before:

After:

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. Visit a few different sites
2. Open a new tab
3. Observe favicons

Reviewer Checklist:

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

Tests

• Adequate test coverage exists to prevent regressions
• Tests should be independent and work correctly when run individually or as a suite ref
• New files have MPL2 license header

[cezaraugusto]

hey Margaryta, sorry for delaying this review for so long. After a quick discussion with the team we believe the best way to handle this problem would be to replace the small icons with the letter/color approach, rather than the approach taken here.

Sorry that we weren’t able to spec this out before you started the fix. Feel free to open a conversation in the issue’s thread if you’re still interested on fixing this the other way. For now I’m closing this PR. Thanks!