This PR updates the email validation regex to enforce stricter rules.
- Disallows emails containing double quotes (e.g., `"user"@example.com`,
`user@"example.com"`, `"user@example.com"`).
- Rejects spaces anywhere in the email (e.g., `user @example.com`).
- Prevents consecutive dots in both local and domain parts (e.g.,
`user..name@example.com`, `user@example..com`).
- Allows standard formats like `user@example.com` and
`user.name+alias@example.co.uk`.
Fixes#11755
875afccec4