feat(integrations): add retry header (#2917)

## Describe your changes
As seen in the docs:

![image](https://github.com/user-attachments/assets/97675643-73fd-42ff-935d-395c01b40d87)


## Issue ticket number and link

## Checklist before requesting a review (skip if just adding/editing
APIs & templates)
- [ ] I added tests, otherwise the reason is: 
- [ ] I added observability, otherwise the reason is:
- [ ] I added analytics, otherwise the reason is:

packages/shared/providers.yaml

@@ -2663,6 +2663,8 @@ gorgias:
         grant_type: refresh_token
     proxy:
         base_url: https://${connectionConfig.subdomain}.gorgias.com
+        retry:
+            after: 'Retry-after'
     docs: https://docs.nango.dev/integrations/all/gorgias
     connection_config:
         subdomain: