fix: Update SNS capture_serverless test

Author: jackylamhk

tests/contrib/serverless/aws_sns_test_data.json

@@ -27,6 +27,10 @@
                     "City": {
                         "Type": "String",
                         "Value": "Any City"
+                    },
+                    "traceparent": {
+                        "Type": "String",
+                        "Value": "00-0af7651916cd43dd8448eb211c80319c-b7ad6b7169203331-00"
                     }
                 }
             }

tests/contrib/serverless/aws_tests.py

@@ -344,6 +344,8 @@ def test_func(event, context):
     assert transaction["span_count"]["started"] == 1
     assert transaction["context"]["message"]["headers"]["Population"] == "1250800"
     assert transaction["context"]["message"]["headers"]["City"] == "Any City"
+    assert len(transaction["links"]) == 1
+    assert transaction["links"][0] == {"trace_id": "0af7651916cd43dd8448eb211c80319c", "span_id": "b7ad6b7169203331"}
 
 
 def test_capture_serverless_sqs(event_sqs, context, elasticapm_client):