Ensure API key util actually returns API key

🤦

Author: JoshMock

test_elasticsearch_serverless/utils.py

@@ -187,3 +187,4 @@ def es_api_key() -> str:
     api_key = os.environ.get("ES_API_KEY", None)
     if api_key is None:
         raise RuntimeError("No ES_API_KEY environment variable provided")
+    return api_key