Deprecate `extents` prop perhaps?

[mhkeller]

Setting the domain via xDomain, yDomain, rDomain or zDomain is very similar to setting it via extents with the exception that domains set via extents skip measuring the extent for that dimension.

Instead of having this as a separate prop, dimensions could be skipped if a domain is passed into the _Domain props and it contains no null values.

In any event, this can wait until Svelte 5 is out since it would be a breaking change.