Fix DLQ test timing and receive count logic

- Increase receive attempts from 2 to 3 to ensure maxReceiveCount is exceeded
- Adjust visibility timeout wait from 3s to 2.5s to match queue config
- Increase DLQ receive wait time from 2s to 5s for better reliability
- Add extra 1s wait after failure simulation for DLQ processing

Author: NinjaRocks

tests/SourceFlow.Cloud.AWS.Tests/Integration/AwsDeadLetterQueueProcessingTests.cs

@@ -145,27 +145,29 @@ public async Task DeadLetterProcessing_ShouldCaptureCompleteMetadata()
 
         Assert.NotNull(sendResponse.MessageId);
 
-        // Act - Simulate processing failures
-        for (int attempt = 1; attempt <= 2; attempt++)
+        // Act - Simulate processing failures by receiving without deleting
+        // The message will be moved to DLQ after maxReceiveCount (2) attempts
+        for (int attempt = 1; attempt <= 3; attempt++)
         {
             var receiveResponse = await _localStack.SqsClient.ReceiveMessageAsync(new ReceiveMessageRequest
             {
                 QueueUrl = mainQueueUrl,
                 MaxNumberOfMessages = 1,
                 MessageAttributeNames = new List<string> { "All" },
                 AttributeNames = new List<string> { "All" },
-                WaitTimeSeconds = 1
+                WaitTimeSeconds = 2
             });
 
             if (receiveResponse.Messages.Any())
             {
                 // Don't delete - simulate failure
-                await Task.Delay(3000);
+                // Wait for visibility timeout to expire so message becomes available again
+                await Task.Delay(2500); // Slightly longer than VisibilityTimeout (2s)
             }
         }
 
-        // Wait for DLQ processing
-        await Task.Delay(2000);
+        // Wait a bit more for DLQ processing to complete
+        await Task.Delay(1000);
 
         // Act - Retrieve from DLQ and process
         var dlqReceiveResponse = await _localStack.SqsClient.ReceiveMessageAsync(new ReceiveMessageRequest
@@ -174,7 +176,7 @@ public async Task DeadLetterProcessing_ShouldCaptureCompleteMetadata()
             MaxNumberOfMessages = 1,
             MessageAttributeNames = new List<string> { "All" },
             AttributeNames = new List<string> { "All" },
-            WaitTimeSeconds = 2
+            WaitTimeSeconds = 5
         });
 
         // Assert - Message should be in DLQ