Order two_factor_enabled short-circuiting by usage

[aduth]

🛠 Summary of changes

Reorders checks in MfaContext#two_factor_enabled? to assure higher likelihood of short-circuiting, based on setup rates for common MFAs.

CloudWatch query:

filter name = 'Multi-Factor Authentication Setup'
| stats count(*) as method_count by properties.event_properties.multi_factor_auth_method
| sort method_count desc

📜 Testing Plan

This performs the same checks so it shouldn't have any notable effects.

Verify associated specs pass:

rspec spec/decorators/mfa_context_spec.rb