[cr105 follow up] Fixes favicon in Shields Panel.

[mkarolin]

Fixes brave/brave-browser#24954

The chrome://favicon2 syntax has changed to camelCase.

Chromium change:

https://source.chromium.org/chromium/chromium/src/+/78e45e119c9aca1eabf7e0b23764d1923f25a720

commit 78e45e119c9aca1eabf7e0b23764d1923f25a720
Author: Solomon Kinard solomonkinard@chromium.org
Date: Mon Jun 13 23:45:53 2022 +0000

Favicon: Use camelCase params instead of snake_case in JS context

Doc:
https://docs.google.com/document/d/1ksvSq1zF-9jYSfGOvNluyoTV0Ud9xl6r9HiAKONqmz8

Context: crrev.com/c/3673461

Bug: 104102

Submitter Checklist:

• I confirm that no security/privacy review is needed, or that I have requested one
• There is a ticket for my issue
• Used Github auto-closing keywords in the PR description above
• Wrote a good PR/commit description
• Squashed any review feedback or "fixup" commits before merge, so that history is a record of what happened in the repo, not your PR
• Added appropriate labels (QA/Yes or QA/No; release-notes/include or release-notes/exclude; OS/...) to the associated issue
• Checked the PR locally: npm run test -- brave_browser_tests, npm run test -- brave_unit_tests, npm run lint, npm run gn_check, npm run tslint
• Ran git rebase master (if needed)

Reviewer Checklist:

• A security review is not needed, or a link to one is included in the PR description
• New files have MPL-2.0 license header
• Adequate test coverage exists to prevent regressions
• Major classes, functions and non-trivial code blocks are well-commented
• Changes in component dependencies are properly reflected in gn
• Code follows the style guide
• Test plan is specified in PR before merging

After-merge Checklist:

• The associated issue milestone is set to the smallest version that the
  changes has landed on
• All relevant documentation has been updated, for instance:
  • https://github.com/brave/brave-browser/wiki/Deviations-from-Chromium-(features-we-disable-or-remove)
  • https://github.com/brave/brave-browser/wiki/Proxy-redirected-URLs
  • https://github.com/brave/brave-browser/wiki/Fingerprinting-Protections
  • https://github.com/brave/brave-browser/wiki/Brave%E2%80%99s-Use-of-Referral-Codes
  • https://github.com/brave/brave-browser/wiki/Custom-Headers
  • https://github.com/brave/brave-browser/wiki/Web-Compatibility-Exceptions-in-Brave
  • https://github.com/brave/brave-browser/wiki/QA-Guide
  • https://github.com/brave/brave-browser/wiki/P3A

Test Plan:

[nullhook]

lgtm