Azure web app behind cloudflare - is custom domain cert still needed?

We have an azure web app that has a custom domain (let’s call it MyCustomDomain.com) which of course we have SSL certs for.
Azure web apps also have internal domains which come with their own SSL (eg mycustomdomain.azurewbsites.net)
We’ve put Cloudflare in front of the web app so now MyCustomDomain.com resolves to cloudflare etc… and we’re now using the Cloudflare SSLs for that domain.

Does anyone know if I need to keep the MyCustomDomain.com SSL attached to the web app in Azure? (I’m assuming that the *.azurewebsites.net cert is sufficient for the traffic between Cloudflare and the web app).

I’m currently creating a new instance of the web app with a different IP address and it would be nice not to have the original cert on there if I don’t need it.

Cheers,
M