fix: update opensearch_url for aoss

Author: hvital

lambda/aws-qa-appsync-opensearch/question_answering/src/qa_agent/helper.py

@@ -109,9 +109,10 @@ def load_vector_db_opensearch(region: str,
         )
     embedding_function = get_embeddings_llm()
 
+    opensearch_url = opensearch_domain_endpoint if opensearch_domain_endpoint.startswith("https://") else f"https://{opensearch_domain_endpoint}"
     vector_db = OpenSearchVectorSearch(index_name=opensearch_index,
                                        embedding_function=embedding_function,
-                                       opensearch_url=f"https://{opensearch_domain_endpoint}",
+                                       opensearch_url=opensearch_url,
                                        http_auth=http_auth,
                                        use_ssl = True,
                                        verify_certs = True,