Constraints should be checked in parallel.

[Jonas-Sander]

Instead of iterating through the constraints we should execute them in parallel via .map as await blocks the loop until resolved.

    for (final constraint in jwtConstraints) {
      final satisfied = await constraint.isSatisfiedBy(jwt);
      _logger.finer(
          'JWT-Token constraint ${constraint.description} satisfied: $satisfied');
      if (!satisfied) {
        throw ArgumentError(
            'JWT does not satisfy constraint: ${constraint.description}');
      }