Little fix while generating some PDF

[shawe]

This fixes some issues when generating some PDF.

• L672: $num is defined in PHPDoc has int, but default value was an empty string. Without this change, pagination is always 0 of 0 when this parameter is not specified by default.
• L1544: An empty string is not array or countable. Without this change, it was outputing warning messages like this: Warning: count(): Parameter must be an array or an object that implements Countable in vendor/rospdf/pdf-php/src/Cezpdf.php on line 1544. Maybe is a better solution replace '$fillColor && ' by '!empty($fillColor) && '.