Remove invalid comma in json testing template (#448)

* The `otelSDKexpectedAWSSDKTrace.mustache` file had an extra comma that made it invalid JSON

Author: NathanielRN

validator/src/main/resources/expected-data-template/otelSDKexpectedAWSSDKTrace.mustache

@@ -22,7 +22,7 @@
         }
       },
       "aws": {
-        "operation": "ListBuckets",
+        "operation": "ListBuckets"
       },
       "namespace": "aws"
     }