Fix Expected Exception Check in BlobstoreCacheService (elastic#63474) (…

…elastic#64134)

The `NodeNotConnectedException` exception can be nested as well in the
fairly unlikley case of the disconnect occuring between the connected check
and actually sending the request in the transport service.

Closes elastic#63233

x-pack/plugin/searchable-snapshots/src/main/java/org/elasticsearch/blobstore/cache/BlobStoreCacheService.java

@@ -254,10 +254,13 @@ public void onFailure(Exception e) {
     }
 
     private static boolean isExpectedCacheGetException(Exception e) {
-        return TransportActions.isShardNotAvailableException(e)
+        if (TransportActions.isShardNotAvailableException(e)
             || e instanceof ConnectTransportException
-            || e instanceof ClusterBlockException
-            || ExceptionsHelper.unwrapCause(e) instanceof NodeClosedException;
+            || e instanceof ClusterBlockException) {
+            return true;
+        }
+        final Throwable cause = ExceptionsHelper.unwrapCause(e);
+        return cause instanceof NodeClosedException || cause instanceof ConnectTransportException;
     }
 
     public void putAsync(String repository, String name, String path, long offset, BytesReference content, ActionListener<Void> listener) {