Small UI bug in SimpleCommunication c# sample

[lovettchris]

Which sample are you reporting a bug in?

Example: SimpleCommunication

Describe the bug
When you start streaming the overlay doesn't go away

Bug isin LoopbackClientButton_Click, it needs to hide the HiddenVideo.Visibility.

To Reproduce
Steps to reproduce the behavior:

1. clone the samples
2. run the SimpleCommunication C# sample
3. Click Start Preview
4. Click Start Streaming

Expected behavior
Should be able to see both view previews, but instead the streaming preview is hidden behind the localhost_preview_poster.png.

Screenshots

Configuration

• Language/architecture/flavor: C#/WinRT x64 Debug
• Windows platform and build number: Desktop build 22621

• Additional context
  Add any other context about the problem here.