feat: implement check_uniqueness validation in parse_price_feed_updates_internal

- Add uniqueness checking logic when check_uniqueness parameter is true
- Require minAllowedPublishTime > prevPublishTime for uniqueness validation
- Return PythReceiverError::PriceFeedNotFoundWithinRange when uniqueness check fails
- Retrieve previous publish time from latest_price_info storage

Co-Authored-By: ayush.suresh@dourolabs.xyz <byteSlayer31037@gmail.com>

Author: devin-ai-integration[bot]

target_chains/stylus/contracts/pyth-receiver/src/lib.rs

@@ -389,6 +389,16 @@ impl PythReceiver {
                                 return Err(PythReceiverError::PriceFeedNotFoundWithinRange);
                             }
 
+                            if check_uniqueness {
+                                let price_id_fb = FixedBytes::<32>::from(price_feed_message.feed_id);
+                                let prev_price_info = self.latest_price_info.get(price_id_fb);
+                                let prev_publish_time = prev_price_info.publish_time.get().to::<u64>();
+                                
+                                if prev_publish_time > 0 && min_allowed_publish_time <= prev_publish_time {
+                                    return Err(PythReceiverError::PriceFeedNotFoundWithinRange);
+                                }
+                            }
+                            
                             let price_info_return = (
                                 U64::from(publish_time),
                                 I32::from_be_bytes(price_feed_message.exponent.to_be_bytes()),