Embedded YouTube with specified timestamp do not load

[brainwo]

This affecting the following pages:
https://docs.flutter.dev/resources/videos
https://docs.flutter.dev/platform-integration/web

The embed link didn't get parsed correctly:

# {% ytEmbed 'lpnKWK-KEYs?start=1712', 'What's new in Flutter - WebAssembly' %}
https://www.youtube.com/embed/lpnKWK-KEYs%3Fstart%3D1712?autoplay=1&start=0&null

Expected link:

https://www.youtube.com/embed/lpnKWK-KEYs?start=1712&autoplay=1&start=0&null