Decoded /leagues-classic/{league_id}/standings/ response.
league describes the league itself; standings is the current page of
ranked entries; has_next indicates whether further pages exist.
Summary
Types
@type t() :: %ExFPL.ClassicStandings{ has_next: boolean(), league: map(), new_entries: [map()], page: integer(), standings: [ExFPL.ClassicStandings.Standing.t()] }