[feature request] Make DPS Queries testable

https://github.com/Azure/azure-iot-sdk-csharp/blob/main/provisioning/service/src/Config/QueryResult.cs

The QueryResponseClass needs to be modifiable to allow testing of applications that query the DPS.

I'm happy to do the work, just looking for guidance on how you would like to proceed.

Start with provisioning/service/src/Config/QueryResult.cs and inspect QueryResponseClass and the surrounding DPS query response flow. Determine which parts currently prevent applications from modifying responses for tests; done means an application can create or modify a query response for DPS testing, with the expected behavior verified by the project’s existing tests.

Written by the indexing model from the issue text.