Show troubleshooting options consistently across all MFA verification

[aduth]

🎫 Ticket

Related to LG-10286

🛠 Summary of changes

Updates MFA verification to use a common troubleshooting options module at the bottom of the page, so that users aren't confused by differing content layouts between MFA methods. You should be able to see the adoption of consistently pretty obviously by a cursory glance of the Before/After screenshots below.

📜 Testing Plan

1. Go to http://localhost:3000
2. Sign in
3. When prompted for MFA, observe troubleshooting options
   • In most cases, this should be consistently "Choose another authentication method" and "Learn more about authentication options", though some pages have specific additional help (e.g. phone "I didn't receive my one-time code", or restrictions such as PIV-only or AAL2-phishing-resistant, which currently still show the appropriate option, but will be changed as part of future work in LG-10286).

👀 Screenshots

Method	Before	After
Backup codes
Face/Touch Unlock
Personal Key
Phone
PIV
Security Key
Authentication App

[aduth]

I think this and the spec/features/users/sign_in_spec.rb are another case of not_to assertions passing without any actual relevance to the page. I'm assuming earlier iterations of these screens may have had mentions of specific MFAs, rather than leading back to the MFA selection screen via "Choose another authentication method". It only became a problem when we removed the string.

[aduth]

At one point it seems that we may have prevented the user from returning to the MFA selection during account setup during HSPD12, but as above, the to_not wasn't doing anything meaningful here, and we've shown an option to return to the MFA selection for at least a while now. But the MFA selection does prevent the user from choosing anything other than PIV.

[jmdembe]

Tested locally and LGTM