Add tracking to the phone_verification_for_low_risk_users experiment

What does this MR do and why?

Add tracking to the phone_verification_for_low_risk_users experiment

1. when finishing registration
2. when creating a namespace
3. when banning a user

Issue: https://gitlab.com/gitlab-org/modelops/anti-abuse/team-tasks/-/issues/264

How to set up and validate locally

1. Setup Snowplow Micro for GDK

2. Enable identity verification and the experiment in the console (the Arkose Labs public and private API keys can be found in the 1Password Engineering Vault entry named ArkoseLabs API keys > GITLAB - DEVELOPMENT - REGISTRATION FLOW):

   Feature.enable(:phone_verification_for_low_risk_users)
   Feature.enable(:identity_verification)
   Feature.enable(:identity_verification_phone_number)
   Feature.enable(:arkose_labs_signup_challenge)
   ApplicationSetting.current.update(email_confirmation_setting: 2, require_admin_approval_after_user_signup: false)
   ApplicationSetting.current.update(arkose_labs_public_api_key: '***', arkose_labs_private_api_key: '***', arkose_labs_namespace: 'client')

3. Create a new account on http://localhost:3000/users/sign_up

4. Update the arkose risk score of the new user to Low

   User.last.custom_attributes.by_key(UserCustomAttribute::ARKOSE_RISK_BAND).update(value: 'Low')

5. Refresh the page (http://localhost:3000/users/identity_verification) and verify the user needs to verify both phone number and email:

   

6. Open Snowplow Micro page on http://localhost:9091/micro/good and verify assignment event has been tracked

7. Repeat after creating a group during registration and after banning

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.