Investigation: disposal/stop paths ordering

A customer had an issue with an EventHub-triggered function which was throwing the error `DryIoc.ContainerException : Container is disposed and should not be used: Container is disposed.` on shutdown. We have determined from the logs that this is because the host is disposing before the RPC service. Disposal may be occurring in the stop path, and vice-versa.

related issue: #4190, and associated PR #4590.

Associated IcM incident: [175136273](https://icm.ad.msft.net/imp/v3/incidents/details/175136273/home)

@pragnagopa @yojagad @mhoeger @fabiocav

Start by reading related issue #4190 and associated PR #4590, then trace the host and RPC disposal and stop paths implicated by the logs. Determine the shutdown ordering that causes the disposed-container error; done means the expected ordering is established and the host does not dispose before the RPC service.

Written by the indexing model from the issue text.