Explore adding an overload to the `to_<topology>` transforms that accepts a coordset name directly and skips coordset creation

[siramok]

While exploring #1646, we realized that there are various internal calls to to_unstructured that only care about the topology output. Since to_unstructured always creates a coordset, even if it will just be thrown away afterwards, we think it would be better to explore overloading the API to have a version of to_unstructured that skips coordset creation entirely by taking the coordset name as a string. 1) This is more efficient and 2) it alleviates the problem of needing a strange pattern for calling to_unstructured to ensure that a coordset name is always set.

[JustinPrivitera]

It would be good to do this for the other topology transforms as well, and then to audit the uses around the code base to ensure we are only generating a coordset when actually needed.

[siramok]

Makes good sense to me.