Merged PR 16981: Only update catalog if orders found

## What's being changed

Order sync.

## Why it's being changed

In the event that no orders were found to sync, an SQL exception was thrown at `updateCatalog()`.

## How to review / test this change

- Check you have no orders to sync
- Run `n98-magerun sys:cron:run ddg_automation_order_and_quote_sync`
- No output in exception.log

Related work items: #99875

code/Dotdigitalgroup/Email/Model/Sales/Order.php

@@ -103,9 +103,12 @@ public function sync()
                     $this->_setImported($orderIdsForSingleSync, true);
                 }
             }
-
-            // Mark ordered products as unprocessed
-            $this->updateCatalog(array_merge($orders, $ordersForSingleSync));
+
+            if ($this->countOrders > 0) {
+                // Mark ordered products as unprocessed
+                $this->updateCatalog(array_merge($orders, $ordersForSingleSync));
+            }
+
             unset($this->accounts[$account->getApiUsername()]);
         }