(authentication/configuration/restrictions): update block email subaddress behavior

[NicolasLopes7]

Important

🔎 Previews:

• https://clerk.com/docs/pr/1645

Explanation:

We're changing how the block email subaddress restriction works.

Before:

[email protected] would be blocked, as the e-mail contains a +

Now:

🧑‍🦱 A legit user trying to be organized with their mailbox:

• I want to sign up for a new bank that uses Clerk.
• I sign up with an email containing a subaddress: [email protected].
• ✅ Sign-up should be successful.

🎩 An attacker trying to abuse subaddressing:

• They sign up with the first account: [email protected].
• ✅ Sign-up is successful.
• Now they try to sign up again with [email protected].
• ❌ The attempt fails because the same canonical identifier already exists.

[github-actions]

Hey, here’s your docs preview: https://clerk.com/docs/pr/1645