[LIBSEARCH-1031] ACCOUNT: Update Settings display to match Figma diagram

[erinesullivan]

Overview

This pull request was originally focused on LIBSEARCH-1031, but the changes were already made. The focus then shifted to CSS and icon changes:

• Used native CSS to style the radio buttons, and removed the need for the icons.
• Used CSS for the arrow icon in the dropdown and removed the need for JavaScript for styling.
• Updated the Material Icons import to only grab the necessary icons instead of the whole font family, improving load time.
• Removed unnecessary CSS files.

Much more could be done, but this was already way out of scope.

Testing

• Run the tests to make sure they pass (docker-compose run --rm web bundle exec rspec).
• Make sure the PR is consistent in these browsers:
  • Chrome
  • Firefox
  • Safari
  • Edge
• Run accessibility tests:
  • WAVE
  • ARC Toolkit
  • axe DevTools
• Poke around the site to see if anything is broken.
  • Do the icons load faster?