fix: Set '@typescript-eslint/return-await' rule to 'always' for node code (no-changelog) (#8363)

Co-authored-by: कारतोफ्फेलस्क्रिप्ट™ <aditya@netroy.in>

packages/@n8n/nodes-langchain/nodes/agents/OpenAiAssistant/OpenAiAssistant.node.ts

@@ -380,6 +380,6 @@ export class OpenAiAssistant implements INodeType {
 			returnData.push({ json: response });
 		}
 
-		return this.prepareOutputData(returnData);
+		return await this.prepareOutputData(returnData);
 	}
 }