fix(payments): enhance YooKassa webhook processing and notification handling

Improve error handling for YooKassa payment events by adding verification for the payment service configuration. Refactor notification sending for expired discounts to batch messages before sending, ensuring better performance and error logging.

bot/services/promo_code_service.py

@@ -81,6 +81,8 @@ class PromoCodeService:
             return
 
         now_utc = datetime.now(timezone.utc)
+        notifications_to_send: list[tuple[int, str]] = []
+
         async with self._async_session_factory() as session:
             expired_discounts = await active_discount_dal.get_expired_active_discounts(
                 session,
@@ -116,17 +118,7 @@ class PromoCodeService:
                     code_part=(f" (<code>{promo_code}</code>)" if promo_code else ""),
                 )
 
-                try:
-                    await self.bot.send_message(
-                        chat_id=expired.user_id,
-                        text=message_text,
-                        parse_mode="HTML",
-                    )
-                except Exception:
-                    logging.exception(
-                        "Failed to send discount expiration message to user %s",
-                        expired.user_id,
-                    )
+                notifications_to_send.append((expired.user_id, message_text))
 
                 logging.info(
                     "Expired discount reservation removed: user=%s, promo=%s",
@@ -136,6 +128,19 @@ class PromoCodeService:
 
             await session.commit()
 
+        for user_id, message_text in notifications_to_send:
+            try:
+                await self.bot.send_message(
+                    chat_id=user_id,
+                    text=message_text,
+                    parse_mode="HTML",
+                )
+            except Exception:
+                logging.exception(
+                    "Failed to send discount expiration message to user %s",
+                    user_id,
+                )
+
     async def apply_promo_code(
         self,
         session: AsyncSession,