Unable to invoke non-HTTP triggered functions with `cardinality: many` using admin API

#### What language does your question apply to? (e.g. C#, JavaScript, Java, All)

All

#### Question

As per our [docs](https://learn.microsoft.com/en-us/azure/azure-functions/functions-run-local?tabs=v4%2Cwindows%2Ccsharp%2Cportal%2Cbash#non-http-triggered-functions), there is a way for customers to test their functions locally using core tools and the admin API.

We received an issue related to this from a customer using a Python Event Hubs function regarding lack of clarity on the schema expected for the request body. They were able to get it to work when the function was set to `cardinality: one`, but not with `cardinality: many`.

I tried testing both the Kafka and Event Hub extensions with `cardinality: many`, but I was also unable to get it to work, even after some help from the Python-worker team (cc: @gavin-aguiar). I was unable to get it to work in other languages (Node, C#).

I am still unsure if there is way to do this using the admin APIs, or this is unsupported. If it is supported, an improvement in the docs would be helpful.

#### Additional context

There are existing issues about this on the Python-worker repo as well.
https://github.com/Azure/azure-functions-python-worker/issues/764
https://github.com/Azure/azure-functions-python-worker/issues/773

(cc: @alrod as this was discussed with him before).

Start with the linked non-HTTP-triggered functions documentation and the admin API behavior for Event Hubs and Kafka functions using cardinality: many. Review the related Python-worker issues 764 and 773 for existing findings. Done means determining whether this invocation is supported and, if so, documenting the expected request schema or identifying the host behavior that must change.

Written by the indexing model from the issue text.