Merged PR 60657: Use array_unique for category names

## What's being changed

The output of categories in sales data export.

## Why it's being changed

This was a small regression from the recent refactor. Category names should only be listed once i.e.
```
"MOST_PUR_CATEGORY":"Tees,Performance Fabrics,Default Category"
```
not
```
"MOST_PUR_CATEGORY":"Tees,Tees,Performance Fabrics,Default Category"
```

## How to review / test this change

- To reproduce this happening the wrong way you would need a product in an order line item that had nested categories with the same name as the parent
- Confirm category values are correct

Related work items: #280801

Model/Connector/ContactData.php

@@ -453,7 +453,7 @@ private function getCategoryNamesFromIds(array $categoryIds): string
             $names[] = $this->categoryNames[$storeId][$id];
         }
 
-        return (count($names)) ? implode(',', $names) : '';
+        return (count($names)) ? implode(',', array_unique($names)) : '';
     }
 
     /**