Don't allow U2F set up unless an authenticator app is set up

Closes #17333 (closed)

TODO

• #17333 (closed) Authenticator should be set up before enabling U2F
  • Implementation
  • Fix/add tests
  • Refactor
  • Wait for build to pass
  • Assign to endboss for review
  • Address @DouweM's comments
    • No need for javascript:void(0)
    • Add screenshots
  • Wait for merge

Screenshots