feat(webauthn): Skip 2FA for user verified logins

[mimi89999]

A WebAuthn login with user verification is already a second factor, so do not ask for an additional 2FA challenge

• Resolves: Disable 2FA when Webauthn is being used. #21215

Summary

WebAuthn optionally performs user verification: a PIN or a fingerprint is checked on the device itself. That is effectively MFA, something the user has plus something the user knows.

This PR skips the 2FA challenge for those logins. Keys without user verification still go through the usual challenge.

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

AI (if applicable)

• The content of this PR was partly or fully generated using AI

[mimi89999]

@susnux is it expected that the check are failing for this PR?

[golemusu]

splendid. What is your estimate that if/when this is integrated to main branch how long it will actually take for the feature to be available for use e.g. for me (I am using Nextcloud in Hetzner, it seems to be a bit more conservative of server updates and updated just to 33.0.6) ?

So does it require updating the whole server or is it one of the plugins that just needs to be updated?

[ChristophWurst]

LGTM otherwise

thanks for the PR

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