Hide Brave Rewards button

[mkarolin]

• Adds a new setting "Hide Brave Rewards button" under the Appearance
  section of settings.

• Modifies BraveActionsContainer to allow hiding the Brave Rewards
  action when the setting is turned on, but only when Brave Rewards is
  disabled. Hides the action for Guest sessions.

• Adds a browser test to verify that the button is hidden when expected.

• Fixes various lint complaints in the affected files.

Fixes brave/brave-browser#2975

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:

Automated testing
npm run test -- brave_browser_tests --filter=BraveActionsContainerTest.HideBraveRewardsAction
npm run test -- brave_browser_tests --filter=BraveActionsContainerTest.BraveRewadsActionHiddenInGuestSession

Manual testing

1. Test new settings toggle

• Start Brave browser with a fresh profile and verify that the Brave Rewards action button is shown in the location bar,
• Navigate to brave://settings and verify that Hide Brave Rewards button toggle is present in the Appearance section,
• Toggle the setting and verify that the Brave Rewards action button is no longer shown in the location bar,
• Navigate to brave://rewards and click Yes, I am in button, wait for the rewards page to load,
• Verify that the Brave Rewards action button is now shown in the location bar,
• On the brave://rewards page, toggle Brave Rewards setting,
• Verify that the Brave Rewards action button is no longer shown in the location bar.

2. Test Guest/Tor profile

• Start Brave browser with a fresh profile and verify that the Brave Rewards action button is shown in the location bar,
• Click on the Avatar menu -> Open Guest window,
• Verify that the Guest window does not show the Brave Rewards action button,
• Close Guest window,
• In the original window, click on the Avatar menu -> Open Tor window,
• Verify that the Tor window does not show the Brave Rewards action button,
• Close Tor window.

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

[bsclifton]

Works great - automated tests look really good too. Nice lint cleanup. Great job on this one! 😄 👍