Add user_id param to secondary email confirmation links

What does this MR do and why?

Add user_id param to secondary email confirmation links

To prepare for de-scoping emails.confirmation_token to be per-user rather than globally unique, we need to ensure the controller has the email.user_id to look up the appropriate email to confirm.

This change ensures the confirmation link only for secondary emails (using the Email model) includes the user_id parameter. This will be used by the confirmations controller to look up the Email record to confirm, once the new index is in place in !214499

References

• See Epic for related MRs in-progress and rollout plan: &20097
• Must be merged after feature flag removal: !213743 (diffs)
• Part of issue: #562035
• Required for de-scoping emails.confirmation_token : !214499

Screenshots or screen recordings

Before	After

How to set up and validate locally

1. Check the Rails mailer preview: https://gdk.test:3443/rails/mailers/devise_mailer/confirmation_instructions_for_secondary_email.html?locale=en
2. Ensure the CTA link has the user_id parameter, similar to: https://gdk.test:3443/-/profile/emails/confirmation?confirmation_token=faketoken&user_id=123

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