Extended submission does not include formVersion

Submission responses have a property named `currentVersion`, which is a submission version object. If extended metadata is requested, a `submitter` property is added to `currentVersion`, which matches what we do for extended submission version objects. However, a `formVersion` property is not added to `currentVersion`. Typically extended submission version objects have a `formVersion` property. If extended metadata is requested, I think it'd be ideal if the `currentVersion` property had all the properties of an extended submission version object. (I think `formVersion` is the only property it's missing.)