Update Zero-downtime deployment for Durable Functions article

The strategies for achieving a zero-downtime deployment described in this [doc](https://learn.microsoft.com/en-us/azure/azure-functions/durable/durable-functions-zero-downtime-deployment) seem to be conflicting. The article itself was also updated a while back.

Read the linked Durable Functions zero-downtime deployment article and compare the strategies described there for internal consistency. Determine which guidance is current before making a documentation update; done means the article presents one clear, non-conflicting deployment approach.

Written by the indexing model from the issue text.