Calling WInUI3

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### This issue is for a: (mark with an `x`)
```
- [ x] bug report -> please search issues before submitting
- [ ] feature request
- [ ] documentation issue or request
- [ ] regression (a behavior that used to work and stopped in a new release)
```

### Minimal steps to reproduce
> When I compile and configure the example, It wil not accept any incomingcalls. The UWP version calling works and can call and be called. The winui3 can only call but can't be called.
Secondly no video is shown in the Mediaplayer element.

### Any log messages given by the failure
> No message what so ever. The incoming call is not handled.

### Expected/desired behavior
> Receiving and handling the incoming call from the SDK.
Showing the video streams in the media player elements

### OS and Version?
> Windows 10

### Versions
>

### Mention any other details that might be useful

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