Remove sync/sign in language from avatar menu.

[mkarolin]

Fixes brave/brave-browser#2234

This fix modifies the current profile's button in the avatar popup menu.
It removes the sync overlay from the profile icon and replaces "Sync
disabled"/"Not signed in" labels with the profile's name.

Adds a browser test to verify that the button shows profile name.

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 test:
npm run test -- brave_browser_tests --filter=BraveProfileChooserViewTest.TestCurrentProfileView

Manual test:

• Start Brave browser,
• Click on the avatar menu button in the toolbar,
• Verify that the first button in the menu shows profile avatar with no overlays and the text is the name of the profile.
• Click on the button - this should result in profile settings page showing up,
• In the profile settings page change the profile name,
• Click on the avatar menu button again,
• Verify that the profile button shows the new name.

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

[darkdh]

++

[mkarolin]

master: 3e0028d
0.59.x: daf1680

[kjozwiak]

@mkarolin approving uplift request to 0.58.x after deliberating with @rebron & @srirambv 👍Please make sure that all the appropriate labels are removed/added and the corresponding issue is moved to the correct milestone.

[mkarolin]

0.58.x: 12882ce