Renewing Durable Functions Host Key in Portal results in two keys

For an Azure Functions app with the Durable Functions extension installed, I went to the Manage tab in the portal for a function and clicked the "Renew" icon to renew the `durabletask_extension` key. This resulted in **two** host keys with the name `durabletask_extension`, and the new one is not valid for calling the Durable Functions API, and the original one still works.


I've reproduced this on two separate Function Apps

Start by reproducing the issue from the Azure portal Manage tab using the Renew icon for the durabletask_extension host key. Trace the host-key renewal path and verify that renewal does not leave duplicate keys, that the replacement key works for the Durable Functions API, and that the expected old-key behavior is preserved.

Written by the indexing model from the issue text.