[Feature] WindowsProvider should display message if app is not Store associated

## Describe the problem this feature would solve

In order for the [WindowsProvider](https://docs.microsoft.com/en-us/windows/communitytoolkit/graph/authentication/windows) to work, the app must be associated with the Microsoft Store. This is done through Visual Studio as described [here](https://docs.microsoft.com/en-us/windows/mixed-reality/distribute/submitting-an-app-to-the-microsoft-store#associate-app-with-the-store) (Ignore the fact that these are the MR docs. It works the same and I couldn't find any generic guidance for UWP.)

It's not always immediately obvious to a developer that they need to do this, which can lead to folks getting stuck, "Hey, why doesn't my app work?"

It's in the docs, but is easy to miss.

## Describe the solution

See if we can throw an exception with a descriptive message telling the developer to go do the Store association.,

## Describe alternatives you've considered

None

## Additional context & Screenshots

We currently don't do anything special if the Store association is missing. Auth will just fail without obvious cause.

Start at the WindowsProvider authentication flow and identify where failure occurs when the app lacks Microsoft Store association. Confirm the existing behavior with an unassociated app, then make the failure explain that Store association is required and verify that the message appears in this case.

Written by the indexing model from the issue text.