specifying an external multi-step webTest File into ARM?

**azure-quickstart-templates/201-dynamic-web-tests/**

### Issue Details
Greetings, our team uses ARM templates for deployment of multi-step webtests. We are using ASP.net Core and have been generating the multi-step webtest within our solution itself. I noticed in all ARM template examples for webTests, it does not show an example where one can specify an external webtest. Instead, all of the examples show the webTest configuration as a Xaml string hardcoded with parameters/variables nested inside. Is there a way to specify a path in our Linked ARM template for a multi-step webtest such as the one created in this example?
[Multi-step web tests](https://docs.microsoft.com/en-us/azure/azure-monitor/app/availability-multistep)

Review azure-quickstart-templates/201-dynamic-web-tests/ and the linked Microsoft multi-step web tests guidance first. Determine whether a linked ARM template can reference an external multi-step webTest file rather than an inline XAML string; done means documenting the supported approach or defining the required template change and example.

Written by the indexing model from the issue text.