add description & example

Author: raed667

specs/advanced-personalization/common/schemas/RealtimeUser.yml

@@ -16,6 +16,8 @@ RealtimeUser:
       description: User ID of the user.
     lastUpdatedAt:
       type: string
+      description: Date and time when the profile was last computed, in RFC 3339 format.
+      example: 2023-06-15T15:06:04.249906Z
     search:
       type: object
       description: |