LG-14389: Add analytics for consent screen email selection

[aduth]

🎫 Ticket

LG-14389

🛠 Summary of changes

Logs analytics events when the user visits and submits the email selection screen when prompted to consent to share information with a partner.

This leverages existing analytics events created for changing the selected email for a partner in LG-13665 (#11196), using the property needs_completion_screen_reason to differentiate if the email was changed stemming from the consent screen.

📜 Testing Plan

Prerequisites:

• If you've already consented for the OIDC sample application, sign in and revoke consent from the "Connected accounts" page of your account dashboard
• You must have multiple email addresses associated with your account

Validate that the expected events are logged:

1. Run make watch_events in a separate terminal process
2. Run sample application in a separate terminal process
3. Go to http://localhost:9292
4. Click "Sign in"
5. Sign in
6. When prompted to consent to share information, click "Edit email address"
7. Observe in make watch_events terminal process the event sp_select_email_visited with a needs_completion_screen_reason value
8. Submit the page with your preferred email to share
9. Observe in make watch_events terminal process the event sp_select_email_submitted with success: true and a needs_completion_screen_reason value