Meet: Improvements using participant tiles

[MaxHeimbrock]

Background

We had a very limited UI in the Meet example. This uses a tile prefab with placeholder image for video mute, icon for microphone mute, and displays the participants identity. Cropped videos with black bars (Letterbox) to keep original aspect ratio, which made videos very small. Now crop with fill method.

Changes

• Adds ParticipantTile.cs
• Adds ParticipantTile.prefab
• Participants joining without camera get a placeholder icon
• Participants name is displayed
• Participants microphone mute state is displayed via icon
• Video is cropped by fill method
• Front facing camera is preferred
• Camera permission is triggered when local camera is enabled

Before

Participants without video are not shown. No mic state, no name displayed.

After