Clear Shopify ID for product template no more found on Shopify

If the Shopify ID of a template can not be found on Shopify, there is no need
to keep it as we could not reactivate the Shopify product it is added back.

Closes #14980
(grafted from eb5fcd8c8ed278f9eba8f65e89f07dd3beafe4c3)

--HG--
branch : 8.0

modules/web_shop_shopify/web.py

@@ -666,6 +666,8 @@ class Shop(metaclass=PoolMeta):
                             'web_shop_shopify.msg_product_fail',
                             template=template.rec_name,
                             error=e.message)) from e
+            else:
+                template.set_shopify_identifier(self)
 
     @classmethod
     def shopify_update_inventory(cls, shops=None):