Feature request: expose enablejsapi argument for YouTube embed

[nirfse]

Hello,

I recently needed to control YouTube player behavior across multiple slides, specifically stopping playback of one video when another starts. Unfortunately, svelte_embed doesn't currently expose the enablejsapi URL parameter needed for programmatic control.

Would you consider merging a PR (or implementing by yourself) that exposes this parameter in the component?

Thanks for maintaining this useful package.