56058: Validating latestRun before accessing its properties (apache#56303)

* 56058: Checking for latestRun before invoking isStatePending

* Fixed formatting

---------

Co-authored-by: Vivek Nanda <vnanda@cloudera.com>

Author: viveknanda

airflow-core/src/airflow/ui/src/pages/Dag/Dag.tsx

@@ -108,7 +108,9 @@ export const Dag = () => {
       <DetailsLayout error={error ?? runsError} isLoading={isLoading || isLoadingRuns} tabs={displayTabs}>
         <Header
           dag={dag}
-          isRefreshing={Boolean(isStatePending(latestRun?.state) && Boolean(refetchInterval))}
+          isRefreshing={
+            latestRun ? Boolean(isStatePending(latestRun.state) && Boolean(refetchInterval)) : false
+          }
           latestRunInfo={latestRun ?? undefined}
         />
       </DetailsLayout>