Cannot Re-add a user via Okta after removal

### Environment

SaaS (https://sentry.io/)

### Steps to Reproduce

1. Remove user from Sentry via Okta
2. Add user to Sentry via Okta

### Expected Result

User is able to successfully log into Sentry

### Actual Result

User receives "We found an existing user" screen but they never receive a verification email

### Product Area

Settings - Auth

### Link

_No response_

### DSN

_No response_

### Version

_No response_

Begin in Settings - Auth and trace the Okta remove-and-readd flow described in the reproduction steps. Done means a removed user can be added again through Okta and successfully log in without being trapped on the existing-user screen or missing a verification email.

Written by the indexing model from the issue text.