Error when the Remap del function attempts to delete a path that doesn't exist

[binarylogic]

This is a replacement issue for #5566 to more clearly represent the conclusion there:

So given this, I’m almost inclined to say: when deleting a path, you have to handle the error case for when a path does not exist.

This is blocked on #5479 since we should resolve our error handling primitives first.

[JeanMertz]

We opted not to do this, instead documenting the existence of the exists function to make a distinction between existing null fields or non-existing fields. See the discussions in #5633.