A typed Figma text measurement retaining its source units.
@type kind() :: :letter_spacing | :line_height
@type t() :: %Figler.Render.Text.Measurement{units: units(), value: float()}
@type units() :: :raw | :pixels | :percent
@spec from_sparse(map() | nil) :: t() | nil
@spec pixels(t() | nil, number() | nil, kind()) :: float() | nil