Update post: Add a note about the date old interface was removed (#362)

This adds an update note to the bottom of an existing post, with the
date that the old interface was removed:

<img width="748" height="233" alt="Screenshot 2026-01-27 at 19 52 29"
src="https://github.com/user-attachments/assets/31069e6f-d0db-40fc-bfe5-1b61bde2f463"
/>

Author: frankieroberto

app/record-a-vaccination/2025/10/how-we-told-users-about-a-change-to-the-interface/index.md

@@ -66,6 +66,7 @@ We may send some additional emails to alert users of the removal of the old inte
 
 After 30 November, we also will remove the ‘New’ tags from the header, and remove the guidance page for the old interface.
 
-
+> [!NOTE] Update
+> Removing the old interface was delayed, and took place on 27 January 2026.