fix(vtex): give the birthday matcher its own icon

Change `@icon calendar-event` → `@icon gift`. It previously shared the calendar
icon with the generic Date matcher; a gift gives the birthday matcher its own
identity in the admin's matcher picker.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Author: guitavano

vtex/matchers/birthday.ts

@@ -16,7 +16,7 @@ export interface Props {
 /**
  * @title Birthday
  * @description Target users based on their birth date
- * @icon calendar-event
+ * @icon gift
  */
 const MatchBirthday = async (
   props: Props,