Add debug logging to help with healthcheck issues

Signed-off-by: Yoriyasu Yano <430092+yorinasub17@users.noreply.github.com>

worker/app.ts

@@ -42,5 +42,6 @@ async function handler(msg: Message): Promise<void> {
 }
 
 async function handleHealthCheck(payload: HealthCheckPayload): Promise<void> {
+  console.log(`Received healthcheck for request ${payload.requestID}`);
   await storeHealthCheckResult(payload.requestID);
 }