Tests: filter, group and sort on channel

Test that if filters, group of filters and sorts are set on channels, the generated URLs are OK.

Also, in entity_share/modules/entity_share_server/src/OperatorsHelper.php:

  public static function getMultipleValuesOperators() {
    return [
      'IN' => 'IN',
      'NOT IN' => 'NOT IN',
      'BETWEEN' => 'BETWEEN',
    ];

    // TODO: The following operators are marked as multiple values in JSON:API
    // documentation https://www.drupal.org/docs/8/modules/json-api/collections-filtering-sorting-and-paginating
    // But it does not work. See why.
    // '=' => '=',
    // '<' => '<',
    // '>' => '>',
    // '<>' => '<>',.
  }