Correct call to super method for Shopify name

The name of the property was changed on commit 905801635f45
but the call to super method was not updated to the new name.

Closes #12355

modules/web_shop_shopify/product.py

@@ -612,7 +612,7 @@ class Image_Attribute(metaclass=PoolMeta):
 
     @property
     def shopify_name(self):
-        name = super().shopify_filename
+        name = super().shopify_name
         if self.product:
             attributes_name = self.product.attributes_name
         else: