Running non HTTP-triggered functions with Azure Functions on Azure Container Apps

#### Is your question related to a specific version? If so, please specify:

[Azure Functions on Azure Container Apps](https://learn.microsoft.com/en-us/azure/container-apps/functions-overview) (native)

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

All

#### Question
How do you obtain a master key to use with the `x-functions-key` header to [Manually run a non HTTP-triggered function](https://learn.microsoft.com/en-us/azure/azure-functions/functions-manually-run-non-http?tabs=azure-portal) when using the new [Native Azure Function Support in Azure Container Apps](https://techcommunity.microsoft.com/blog/appsonazureblog/announcing-native-azure-functions-support-in-azure-container-apps/4414039).

I cannot create a `_master` key in the container app and reaching out to `{app}.azurecontainerapps.io/admin/host/systemkeys/_master` returns a 401.

Start with the Azure Functions manual-run documentation and the Native Azure Function Support in Azure Container Apps documentation, then compare their key-management guidance with the reported /admin/host/systemkeys/_master request. Done means documenting the supported way to obtain or create the master key, or clearly stating that this flow is not supported for native Azure Functions on Azure Container Apps.

Written by the indexing model from the issue text.