bug: `src/index/vector/builder.rs:1779:14`: called `Option::unwrap()` on a `None` value

[wjones127]

This occurs while optimizing a IVF_HNSW_SQ/Cosine index.

Originally reported in https://discord.com/channels/1030247538198061086/1456659493659213834

This occurs here:

lance/rust/lance/src/index/vector/builder.rs

Lines 1775 to 1779 in ab5fdb3

	let min_dist_idx = dists
	.values()
	.iter()
	.position_min_by(|a, b| a.total_cmp(b))
	.unwrap();

It's possible the issue is the distance overflowed and thus is infinite. We might have to do something similar to: #4914. Just tested, and infinite and NaN vectors don't disrupt this. It only is None if the vector is empty.

[wjones127]

It looks like this was fixed in #5241