fix(medusa-plugin-brightpearl): only update inventory levels that are out of sync

packages/medusa-plugin-brightpearl/src/services/brightpearl.js

@@ -138,9 +138,12 @@ class BrightpearlService extends BaseService {
         )
         const onHand = availability[productId].total.onHand
 
+        // Only update if the inventory levels have changed
+        if (parseInt(v.inventory_quantity) !== parseInt(onHand)) {
           return this.productVariantService_.update(v._id, {
             inventory_quantity: onHand,
           })
+        }
       })
     )
   }