Add IsIndeterminate to AppNotificationProgressData

### Describe the bug

With the AppNotificationProgressData API, developers cannot set value="indeterminate" to their progress bar toast notification. In XML, setting value="indeterminate" in the progress element creates a loading animation in the progress bar notification. However, this behavior cannot be achieved with the current AppNotificationProgressData API.

Proposed solution: add a boolean isIndeterminate, very similar to the [WCT notification library's builder syntax approach](https://docs.microsoft.com/en-us/windows/apps/design/shell/tiles-and-notifications/toast-schema#adaptiveprogressbarvalue), to AppNotificationProgressData. Bool isIndeterminate would get or set a value indicating whether the progress bar is indeterminate. If isIndeterminate is true, Value will be ignored.

### Steps to reproduce the bug

Existing XML notification functionality is not supported in latest API

### Expected behavior

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### Screenshots

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### NuGet package version

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### Windows version

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### Additional context

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