add seat getter from user id

src/ez_lan_manager/services/SeatingService.py

@@ -45,6 +45,12 @@ class SeatingService:
             if seat.seat_id == seat_id:
                 return seat
 
+    def get_user_seat(self, user_id: int) -> Optional[Seat]:
+        all_seats = self.get_seating()
+        for seat in all_seats:
+            if seat.user and seat.user.user_id == user_id:
+                return seat
+
     def seat_user(self, user_id: int, seat_id: str) -> None:
         user_ticket = self._ticketing_service.get_user_ticket(user_id)
         if not user_ticket: