2-Step Verification is a prerequisite for Gmail's app-passwords page, so
render the twoFactorHelpUrl button first when present, then the
appPasswordHelpUrl button. Previously the prerequisite link rendered
second, so a user without 2FA enabled would hit a dead end on the first
button before noticing the second. No visible change for Yahoo/iCloud,
which have no twoFactorHelpUrl.
Closes#152
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>