fix: cloning algorithm: support for all possible srcObject types

[WofWca]

HTMLMediaElement.srcObject can be a MediaStream, MediaSource, Blob or File (see this). MediaSource could be handled by #2. The rest I have not checked whether the cloning algorithm works for them. Currently we're only copying the src attribute, which doesn't work if the media's source is set with srcObject:

jumpcutter/src/entry-points/content/ElementPlaybackControllerCloning/Lookahead.ts

Lines 83 to 90 in 1db4ef4

	const clone = document.createElement('audio');
	this.clone = clone;
	// TODO this probably doesn't cover all cases. Maybe it's better to just `originalElement.cloneNode(true)`?
	// TODO also need to watch for changes of `crossOrigin`
	// (in `ElementPlaybackControllerCloning.ts`).
	clone.crossOrigin = originalElement.crossOrigin;
	clone.src = originalElement.currentSrc;