fix: handle nullable worker in deployment lookup

Author: ericallam

apps/webapp/app/routes/resources.orgs.$organizationSlug.projects.$projectParam.env.$envParam.test.ai-generate-payload.tsx

@@ -222,7 +222,7 @@ async function getTaskSourceCode(
 
 async function getTaskFromDeployment(environmentId: string, taskIdentifier: string) {
   const deployment = await findCurrentWorkerDeployment({ environmentId });
-  if (!deployment) return null;
+  if (!deployment?.worker) return null;
 
   const task = deployment.worker.tasks.find((t) => t.slug === taskIdentifier);
   if (!task) return null;