Append membership_fee_type to column list when it is visible but
membership_fee_start_date was not in the selection (MemberExport,
export_column_order, build_export_member_fields_list).
Use Ash related-field sort (membership_fee_type.name) instead of
membership_fee_type_id so column order is alphabetical. Load
membership_fee_type when sorting by it even if column is hidden.
In-memory re-sort (Build) uses loaded fee type name.
