Fix Media Element Poster not showing on Windows/iOS/Mac

[ne0rrmatrix]

• Bug fix

Description of Change

Fix Media Element Poster not showing on screen during playback if no video and player is playing audio.

Linked Issues

• Fixes #1976

PR Checklist

• [x] Has a linked Issue, and the Issue has been approved(bug) or Championed (feature/proposal)
• [ ] Has tests (if omitted, state reason in description)
• [x] Has samples (if omitted, state reason in description)
• [x] Rebased on top of main at time of PR
• [x] Changes adhere to coding standard
• [ ] Documentation created or updated: https://github.com/MicrosoftDocs/CommunityToolkit/pulls

Additional information

This is an update that addresses complaints that device behavior is not consistent and this will unify behavior across all supported platforms. A poster from artwork will display if audio only inside the player when media element is active.