Add unit test examples to composer-samples

[OliverZ]

Is your feature request related to a problem? Please describe.
I would like to write unit tests for a bot that is created with Botframework Composer. The checking of the dialogs takes too much time because it can't be automated.

Describe the solution you'd like
Please add samples with unit tests to the composer-samples directory for a bot that is created with Botframework Composer.

Describe alternatives you've considered
I don't know how to implement the examples from the documentation: How to unit test bots or from the Core-Bot.Tests example because they apply to SDK v4 but not to Botframework Composer.

Additional context

• https://docs.microsoft.com/en-us/azure/bot-service/unit-test-bots?view=azure-bot-service-4.0&tabs=csharp
• https://github.com/microsoft/BotBuilder-Samples/tree/main/samples/csharp_dotnetcore/13.core-bot.tests