Backup codes not generated in Ubuntu Firefox

[iandunn]

https://wordpress.slack.com/archives/C08M59V3P/p1700078774860549

The next step would probably be to try and reproduce in a VM. It's worth noting that WebAuthn also wasn't working, but that's probably a separate issue. The main problem is that our code isn't handling errors in webauthn registration gracefully. If credentials.create() et al fail, we should abort and make sure the provider isn't enabled.

If it does succeed, we should make sure the backup codes are generated/displayed.

We should also check how many users have a provider enabled but don't have backup codes. After fixing the bug we can reach out to ask them to manually enable backup codes to prevent losing access to their account.