chore(langchain): add a more falsy check for tool_calls output parser (#8634)

Author: hntrl

langchain/src/agents/tool_calling/output_parser.ts

@@ -33,7 +33,7 @@ export function parseAIMessageToToolAction(
     toolCalls = message.tool_calls;
   } else {
     if (
-      message.additional_kwargs.tool_calls === undefined ||
+      !message.additional_kwargs.tool_calls ||
       message.additional_kwargs.tool_calls.length === 0
     ) {
       return {