Require identity verification for OAuth generated users

What does this MR do and why?

When signing up through an external OmniAuth provider, require identity verification.

Screenshots or screen recordings

identity_verification disabled	identity_verification enabled
identity_verification_disabled	identity_verification_enabled

How to set up and validate locally

1. In rails console enable the identity_verification feature flag

   Feature.enable(:identity_verification)

2. Setup an external OmniAuth provider, such as Google OAuth 2.0
3. Sign up for a new account using the external provider

MR acceptance checklist

This checklist encourages us to confirm any changes have been analyzed to reduce risks in quality, performance, reliability, security, and maintainability.

• I have evaluated the MR acceptance checklist for this MR.