UI - Updates to SI Email Notification Templates

update email templates
- change display from birthdate to only show birth year
- change text wording in the outgoing link to omit page
- remove old link to the old form with pre-populated data

update omit page
- when following the link from email omit page starts with expanded help text (add param in the url)

Start by locating the SI email notification templates and the omit page entry point. Review the current email wording, birthdate display, old pre-populated-form link, and omit-page URL handling. Done means the templates show only the birth year, use the revised link text without “page,” remove the old link, and open the omit page with expanded help text when reached from email.

Written by the indexing model from the issue text.