remove booking_url from GET /places/:id example (never set in code)

backend/docs/API_CONTRACT.md

@@ -131,7 +131,6 @@ HTTP статусы: 400 (Bad Request), 401 (Unauthorized), 403 (Forbidden), 404
   "hourly_rate": 1500,
   "currency": "RUB",
   "min_hours": 2,
-  "booking_url": "https://booking.photoplaces.ru/studio/uuid",
   "rating": 4.8,
   "reviews_count": 24,
   "status": "published",