Allow (require?) setting a Field on enum variant data fields

[Hannah-GBS]

Currently we just set a type, whereas structs allow naming the field with s.field(). It would be nice to have an equivalent e.field() on enum constructors. This would both make the Make Package Enum node nicer as it currently uses data object IDs (which are often ugly for easier parsing of API endpoints) to name the pins on a node, as well as the Break Scope node which currently only displays the name property (absent on package enums) and does not fall back to the ID like Make Package Enum does.