Fix responses API (#529)

Will need to fix these telemetry events for this API later

Author: roblourens

src/platform/openai/node/fetch.ts

@@ -564,7 +564,7 @@ async function fetchWithInstrumentation(
 			throw error;
 		})
 		.finally(() => {
-			sendEngineMessagesTelemetry(telemetryService, request.messages!, telemetryData, false, logService);
+			sendEngineMessagesTelemetry(telemetryService, request.messages ?? [], telemetryData, false, logService);
 		});
 }