feat: убираем денормализацию (антипреждевременная оптимизация)

src/usecase/placement/update_placement.py

@@ -44,6 +44,8 @@ async def update_placement(
     if placement.post:
         ad_post_url = generate_post_url(placement.post.channel.username, placement.post.message_id)
 
+    subscriptions_count = await self.database.count_subscriptions_by_placement(placement.id)
+
     return dto.PlacementOutput(
         id=placement.id,
         project_id=placement.project_id,
@@ -59,6 +61,6 @@ async def update_placement(
         invite_link_type=placement.invite_link_type,
         invite_link=placement.invite_link,
         status=placement.status,
-        subscriptions_count=placement.subscriptions_count,
+        subscriptions_count=subscriptions_count,
         created_at=placement.created_at,
     )